I'm cool with a controlled drop/let-go with heavier DB's, provided there's space. The db's can take more of licking than our shoulders. What does send me into a rage (which can be very productive...in the gym) are the guys that leave like 6 sets pairs of dumbells, no excuse for one pair but 6!!! If you guys saw the freeweight area in my gym tonight, f'ng savages.
I hate when some stupid kid who thinks he's the bomb needs to do some crazy superset with all the dumbbells ranging from 30lb-50lb or something. Or if he has to, at least clean it up after.
If I'm resting inbetween sets and I see stuff lying around I'll even clean up a bit.