The bruised ribs I got by exercising bad judgement: I got between an old woman and the buffet line. Literally, I (and another guy) got bruised ribs from her elbows.
The young parents who insist upon taking toddlers to a 2-hour dinner in the dining room, and then won't take them out when they throw those ear-piercing, head-splitting shrieks.
The people who so inconsiderately insist upon smoking in non-smoking areas.
Having to stand in line the last morning of every NCL cruise to contest charges for in-room water we never drank (wonder how much $$$ they make from people who don't contest the charges)