Store isles crammed with stuff that you can't get your cart through without knocking stuff off racks. Or when stores stick "sales bins" in the aisles so that you can't get around because of people stopped to check the items in the bins.
People that can't at least drive the speed limit. And can't move over.
People that don't control their kids in public places. And I hate it when people let their kids just stare at you over the booth seat. I love kids, but come on! Make the kid sit down and mind his/her own business.
People that during what should be a conservation won't let you get a word in edge wise and the conversation will somehow end up being some way about them.