I don't mind slow people, as long as they have the common courtesy to refrain from blocking the way for everybody else.
If you want to drive 55, get in the slow lane. Take a look in your mirror once in a while - if there are no cars in front of you as far as the eye can see, but the line stretches behind you for a mile, then YOU ARE MOVING TOO DARN SLOW! Get out of the way!
If you are walking along in a city street, store, mall, office building, theme park, or other crowded place, and you need to stop for a moment for some reason, MOVE OVER TO THE SIDE! Slow down a little before you come to a stop instead of coming to a sudden, screeching halt right in the middle of the sidewalk.
If you are walking along with your family, have a look around you once in a while. If there is no room between you and the walls or rails on either side, then you are spread out too wide. Bunch up so other people can get by!
If you are leaving a store, DON'T STOP IN THE DOORWAY! Put away your wallet, look at your reciept, dial your cell phone, tie your shoe, or gab with your friends OUT OF THE WAY!
All of this has to do with either stupidity or apathy - stupid people don't know that their actions affect others, apathetic people don't care that their actions affect others. Stupid or rude - I choose to be NEITHER.