ugh! i totally feel your pain - i live on campus at my school, so i park my car in a communal parking lot all the time, and a few months ago, someone apparently backed into me pulling out of their spot and i now have a softball-sized dent in the back corner of my car. it must have been someone with a truck, because i drive a large SUV and the dent is up above my tail light - a regular car would never have hit it that high.
and the thing is, i'm the BEST parker ever. i take special care to pull up all the way in the spot until my wheels hit so that people can see to get out around me (since i know my car is large and can cause an obstruction), i never ever try to park in a spot that may be too small for the size of my car, and i always park straight, never on an angle. yet the bastard that ran into me and left a LARGE dent, in addition to scraping the paint, can't even leave a note. it's still there, i haven't had time to fix it. makes me a little sad every time i see it, i love my car.