I'm guessing you're applying to a UC, then. From what I understood of the way the two are set up, the Personal Statement is actually designed to be the venue for "passion"--I'd be careful about appearing overeager in your Statement of Purpose, which should be a more professionally written, highly detailed text outlining your plans for study at X school. What I was told about the UC personal statement, when I applied, was that it's meant to show your awareness of the power dynamics inherent to higher academic study and/or how your knowledge of/experience with those power structures plays out in your work/professional goals--basically to show that you are politically sensitive and aware. I'd be interested in hearing how others interpreted it, though.