I hate people who pick the perfect spot on the sidewalk to impede traffic. I wonder if they realize how many times I've had fantasies of tripping and knocking them into traffic. If I am feeling cranky enough I'll try to politely ask them to move. I am getting better at it.
But the thing that bothers me and really shouldn't is when t.v. shows (Breaking Bad is the worst for this) have a person cooking and then they use the sharp side of the blade to push food off the cutting board. I can accept all this other stuff that is pretty over the top in the show but that hits me in the gut like nails on chalk board.