I always got stuck with the top bunk until last semester, I had my own room out in the annex and I pushed the two bunk beds together and had a king sized bed. That was fun.
This semester we had our beds triple bunked and I was stuck in the middle bed which totally sucked b/c it felt like a coffin. Luckily the annoying roommate moved out so now it's just me and my little sis and we have a big room all to ourselves, so we unbunked the beds and both of us get our beds on the floor. Yay for that.
I used to love sleeping on the top bunk when I was a kid though, I had bunk beds in my room but I had my own room, so I could just switch it up every night, sleep up top one night, on bottom the next. Great fun. Yeah, I was a loser when I was kid.
Freshman year when I moved into the dorms I constantly fell out of bed b/c I move around a LOT in my sleep and I had no quite gotten used to small twin beds. Even worse than falling out of bed though was that half the time I would fall off I wouldn't even NOTICE b/c I was in such a deep sleep and I'd just take all my pillows and blankets down with me. So strange.