I have many, but my number one all time pet peeve: People with bad spatial awareness. In other words, people who are inconsiderate of their position in relationship to others when walking and/or driving. If you're walking down a busy street and need to get your sense of where you are or where to go, that's fine, but freaking STEP ASIDE and let others by!!!!!!! Same thing if you're driving. Not sure where to go? Not sure of your GPS directions? No problem, just freaking PULL OVER so other people can continue to go!!! Slowing down to 5 mph is NOT the way to solve this!!! The worst one though is when you're at the store. I understand people need to stop and look for the toy/cereal/bread/sportswear/whatever aisle, I also know sometimes, when you get to the correct aisle, you need to look carefully for that one specific thing you came in to buy. If that is case, then may I suggest you NOT PARK YOUR CART RIGHT WHERE YOU KNOW PEOPLE WILL BE WALKING!!!!!! This is the most maddening thing for me. People leaving their cart right at the opening to an aisle or walkway where you know damn well people will be walking though. Everytime this happens I have to repeat the line from "Dumb and Dumber" when the Killer is being harassed at the pay phone: "did you ever hear of the concept of "other people"?