They always do.
Especially when there are girls around.
I was the idiot the other day. I waited to do bench after I was spent on everything. So Im at the top of my ladder ~215 IIRC, and I have this chick doing back extensions in front of me. I momentarily forget that at this point...Im fricken exhausted and sweaty. I lose my grip, the weight falls on me, then I screamed like a little bitch as i literally caught it right before it smashed my chest and managed to put it back on the bar.