you will meet all kinds of people. don't get offended very often as there will be some ignorants in the bunch. talking about cutthroats, there aren't very many in my field because we try to help each other. but every once in a while, you do bump into one. if they ask for help, help. otherwise, don't get involved in their lives/research, because when time comes, they will back-stab you. also, you will see plenty of dumbs who don't even know that there is a right click in the mouse (trust me, i've seen some). or the types who pay (yes sir, pay a third party) to do their lab AND class work. (see, we are nice, and therefore don't report this to the teachers... mainly because we know that these kind of students will most probably end up flunking their PhD/jobs/whatever and end up doing miserably in their lives). but it is very pathetic that they can't even do their own work. there are also types who think the whole university and grad school thing is about memorizing. they don't think like scientists or philosophers or inventors - for example, their presentation slides (showcasing their research or lab work) will be full of info copied from journals/wikipedia/google, and all they will say during their presentation is 'i am not going to go through all these. i will email my slides to everyone in the class, and you can go through them'. really? that's how you go about publicizing your research? there will also be types who need attention. a LOT of it. if you don't say hi to them (because you are busy doing your work or something), they will stop communication with you whatsoever. there will also be the types who like to play loud music on their ipod and laptops, in front of the group. they think what they watch is funny and awesome, and your opinions don't count - you have to watch/listen to the crap. if not, communications halted.
phew. that looked like a rant!
i assure you, it isn't.. just my recollections of some 'precious' moments in my lab.
anyways, in a nutshell, be yourself, watch the view, and enjoy the ride.