psychIsLife

I think you've gotten a lot of great advice so far, but I'll throw in my two cents!
In my mind, there's nothing more important than fit when choosing a grad program. I applied this cycle straight out of undergrad and was really fortunate to receive offers from two really great clinical programs, and I felt a lot of pressure to accept one of them simply because it's what one is expected to do in that situation. I didn't feel that the fit was terrible with either of them, but it wasn't great either. I thought that the research fit with the PIs was only moderately good, and I didn't feel that I would get quite the high caliber neuropsych training that I was looking for. On the flip side, I had an offer for an RAship with a PI whose research interests are incredibly well-aligned with mine (the general "fit" was great too, in the overall sense of the word).
In the end, I decided to turn down my grad offers and pursue the RAship. I felt such a genuine excitement and eagerness about the RAship that just wasn't there when I thought about the grad programs, and I think it's really important to go where you'll be motivated to perform well. As difficult as it was to turn down the offers (and it really was an agonizing decision process), I just didn't feel comfortable accepting an offer solely because there were offers to accept. Five years is a long time, and those five years are a really formative time in our development as researchers/clinicians, so I want to try to position myself to have the best grad experience that I can. I know it's definitely a risk, and maybe it will or won't lead to an offer from a program with a better fit in the future, but either way, if I can have this great research experience in the interim, I think that alone makes the decision worth it.
With that said, I'm probably on the extreme end when it comes to the importance of fit (especially research fit). A lot of other people think that research fit isn't very important in grad school as long as the PI's work is broadly related to your interests, and that you shouldn't really be concerned with fit until you start looking for post-docs. I'm sure that there's some validity to that, so it's good to try to get as many different perspectives as possible (I probably sought advice from 30+ people before making my final decision). But in the end, despite what everyone else thinks, you just have to make this decision for you and try not to look back. Good luck!

Thanks for your well wishes! I think you know that guilt is not a good reason for making this serious decision, and like you said, if you would just move again soon, that' snot a good idea.
I think sometimes, it's good to be more selfish. We always think of that as a bad thing, but I know for myself (and some of the women in my family), they could use a bit less selflessness. Trust me, it's not good for your health, and its not good for your happiness either.
I really, really wouldn't worry about the justifying aspect. That is way less important than your own well-being. And it's okay if people don't understand, sometimes they don't understand that a place like Columbia isn't actually as a good as U of Akron for some programs (that's true for I/O!), because it sounds better.
And regarding the cog psych ideas, that's partly why we do this, right? Because the things we learn are relevant to everyday life!

Have you experienced what you felt was "good fit" with a PI during an interview? I wasn't really sure what it meant until I had two interviews in a five day period. The first one left me on top of the world thrilled for days while the second one was really disappointing. Even though I was initially very excited about the second school, after the interview I just felt it wasn't right at all, and that was one conversation out of the thousands I'd have with that PI if I went there. With the PI I'll be working with it's hard to imagine I'll ever not want to talk with her. 
It's 40+ hours a week you'll have to work with these people that you may not get along with or not be interested in the work you're doing, for 5-7 years. Grad school really tests you. It's just easier to get through if you're in the right environment, which is why fit is so important. 
Not getting in is scary. I didn't get in my senior year and had to find a job, which I've now been at three years. I have so much more experience and I was a much more competitive applicant this past round. I don't know you but you've got kind of an maybe-scary (job) and a definitely-scary (bad fit school). I'd opt for the maybe-scary, personally. 

I'm not in clinical, but I believe it is pretty important. And here's why I think so:
You can think of it as a luxury, but in reality, it's important whether or not you have lots of choices. As you mentioned, you always have the choice to apply again.
I used to feel the same way as you, I thought I would only apply once because it's a waste not to, and it would make no sense to work for a while or be an RA because that was just stalling and doing something irrelevant when I could be in a graduate program instead. However, I don't feel that way anymore (for a few reasons) and it has definitely changed my outlook. I'll explain more below.
Are you coming out of undergrad right now? Because what I and other people applying directly to PhD programs thought was that we were super ready and anyone else could see that. So we were ambitious and we applied to lots of super competitive schools - spoiler, we didn't get in. Now, that could be for multiple reasons, but one of them was definitely that these places don't often take people right from undergrad. This is especially true for my direct-entry PhD programs, which were in business. But even people in know in areas like vision science were much more competitive after having been an RA or a lab manager for a while. This is especially true for the US - here in Canada, most PhD programs have a funded masters attached, so it's a bit different. Once I realized this, it changed my thinking a bit.
Everything that I just said above is even more true for top programs. When I see the students' backgrounds in these top programs, yes, some of them come in right from undergrad. But others have counselling masters (if they're in clinical), RA positions, or maybe they've worked for a while. Who knows if they just decided to apply later, if they knew this strategy all along, or if they've applied multiple times? No matter which one of these it is, we can see that this waiting/RAing approach has worked very well for them. Of course, there are people it doesn't work well for either, but if you're considering a program right now that is not a good fit and maybe isn't the best place you feel you can get into, then it's a risk but it might make more sense to apply again after.
Here's some cognitive psych applied to this decision for you to consider: people are risk-averse. Like, super risk averse. One bird in the hand is worth two in the bush is a popular expression for a reason. But that doesn't mean it's always the best way for you to make decisions. It can be very suboptimal in certain cases. Is a poor-fitting school right now really better than a great fitting school later, or the option between multiple schools?
Another part of this risk aversion is being bad at forecasting: you might feel right now that you have a higher probability of not getting in anywhere in a second round of applications than you really do. If you got in once, it's really unlikely you will never get in anywhere again. You could very likely get into the same place, or places within that tier, and perhaps some better (objectively and/or better for you) a second time. So your probabilities could be way off. You also have no idea how close you were to being on the waitlist at the other places - you might think you are near the bottom, but you could have barely made the cut, and applying again could bump you over that cutoff.
Fit sometimes has to do with the quality of the school. We say it as if it's totally subjective, but its also a but objective as well. There was one school I interviewed at which had just an atrocious atmosphere and seemed problematic for so many reasons. The funding was crap, the students were unhappy (and they told us), the profs were demanding in ways that didn't make any sense, the program lacked structure, the communication of the program was misleading/incorrect, and there was no ability to even have a conversation with the people who I was supposed to be supervised by. I don't think anyone "fits" within a program like that. So why are we blaming the "fit" or the student for not "fitting", when it's objectively bad? This is broader than just your question, but if you're chalking something up to fit and it's really about your basic needs as a student, then you should keep that in mind. No one "fits" with a place with bad funding, they either make it work because they might have to, or they choose not to go.
A PhD is a super long time. I'm feeling this so much right now. And the thought of working in a place where such major things are a problem (not only your research topics but the structures to support you and how people who are currently there seem to be feeling) is a red flag, not just a bad fit issue. Even where I am, where the support is there, people seem less stressed, and there is (imo) the right balance between freedom and structure, the courses/research/general approach to the field is just not aligned for me. I would consider that more of a fit issue than what you're describing, which sounds more like a bad program issue. But either way, those two kinds of situations likely won't make you happy for 5-6 years.
Also one thing about waitlists: I was on one, and I think the waitlist time gives you a lot of insight into whether you want to go there. I was actually not looking forward to having to make the decision between the waitlist school and the school I eventually chose, and not for good reasons such as liking both of them. I liked one, and I felt like I "should" have chosen the waitlist school, had I gotten in. In a way, I was fortunate that I didn't, because I didn't want to be pulled towards that choice by location (even though its so much better), ranking (again, much better), or overall prestige/how other people would feel (obv related to ranking). Don't go somewhere because you "should", really, it's a bad idea. I know people who are leaving programs now because that's (partly) why they made their decision in the first place.
So this got super long, sorry! I think I really resonated with your question, as I'm dealing with similar things now (from a different stage, more masters to PhD) and there are a lot of commonalities.
Best of luck with your decision!

Just got an acceptance from a program where my PI previously found out he couldn't take any students after the interview. I had an official rejection letter and everything! Just in case anyone needed any hope today that crazy things can still happen.

I feel you... I spent my time coming up with a Plan B, getting excited about other options besides grad school, looking at apartments in my current city to get excited about staying here, looking at conferences coming up, thinking about research ideas in my current lab for pubs/posters, etc... This made the wait SO much easier, to the point where I was so ready and convinced I was going to apply again. However, I diiiiid almost broke down last night over stress and waiting...so I understand.
Hang in there. It's rough but if you're waitlisted places, you're already a competitive candidate and keep that in mind. You're not being dramatic because choosing to go to graduate school means you're passionate about your studies and the rest of your life! Best of luck to you!

This wait gets increasingly harder every day. I feel like I'm being dramatic but maybe this is a shared experience ? Other posters' good fortune is giving me hope though!

That's awesome! Congrats!!  
I agree that even if there probably isn't a risk I'd rather not ask since it doesn't actually make a difference. Thank you again!

Thanks! I was actually accepted off the waitlist from that same program and have accepted the offer, so it all worked out in the end!
Before I asked I got the same vague "alternate for admission" letter, and turns out I was actually first alternate for my POI. So that probably doesn't imply anything about your place on the waitlist.
Chances are it doesn't hurt to ask, but even if the risk of asking is small, it's not really worth taking since knowing won't really affect anything.

Thank you!  I second not wanting to risk asking if you aren't sure--I'd contemplated it for about a milisecond after seeing what seemed like most people on here know their position on the waitlist.  I hope they don't automatically waitlist everyone who interviews, I'd like to think waitlist instead of rejection means something but I could also understand the practicality of it on the school's end--at least they told you they did it that way.  
Oh well, I guess it really doesn't make a difference whether I know my position on the waitlist or not--it won't actually impact the probability of receiving an offer and, really, it would just bring about a different bag of uncertainty to deal with.  I hope everything works out for you!

To inspire a little hope, I was just accepted off the waitlist at Temple! I am so shocked, I thought for sure the person holding it was going to accept at this point. Good luck to everyone else waiting! I hope it all works out

I asked, but only after someone else on the waitlist informed me that they asked and got an answer. Didn't want to risk asking without being sure they would disclose the information.
One of the schools I interviewed at automatically waitlisted everybody at the interviews who weren't given first offers, but they informed us of this. Not sure how common this is. They were a PsyD program and applicants applied to the program, not a POI, so I think their process differs from the usual.

I was in the same boat as you (waitlisted everywhere; it bites I know!). I was told at 2 out of the 4 places I was waitlisted at but for those I was first alternate so I'm sure that they really wanted to keep me available in case the person ahead of me rejected the offer. The other place I was waitlisted at simply said I was waitlisted and they weren't sure how likely an offer was. I would say wait a while and then politely inquire if the waitlist is still active and while re-stating you interest ask what the possibility is of joining the lab at that point.