I think my absolute worst pet peeve is to drive down the street in a beautiful subdivision and see some of the horrible pruning that landscapers do to the trees in the common areas. It makes me want to get out and "fix" the poor things as best I can. So far I've resisted the impulse but if I see a crew out this winter doing their best to maim and kill the trees, I might have to stop and say something. I know it won't do any good but I might feel better for trying.
Ok, rant over. Now it's your turn.