Don't you love when you board first, and then someone comes on later and moves your bag. Or slams something on top of it. Once in FC, I was bringing home a print from overseas, and there was oodles of overhead, but the asshat coming on 10 minutes after me HAD to put his laptop bag directly over his head. The flight was 13+ hours, he needed the exercise, and he decided an argument was more in line than dealing with your fellow passengers. A FA intervened explaining how she could get his bag if needed it a while 4-5 feet away.