So many people do the same nonsensical things over and over that you have to wonder if there is some rule somewhere. A rule that everyone follows but you, and that's why they are annoying. Or mostly annoying. The rule against making eye contact with people in an elevator and the one about keeping space between urinal users help to keep people from feeling creeped out. But most are annoying or even downright passive-aggressive.
Most of these rules could be eased out of existence if we just took other people in account at all. But you might even see yourself in some of them.
Oh come on now. I don't go to McDonald's often. It's rare, actually. And when I do, I look at the menu to see how much my old favorites have gone up in price. And then confusion sets in when I can't find them on the menu at all! Hey, at least I stand back and let other people put their order in while I ponder my options -and budget. See 52 of these unwritten rules (yeah, that's a lot) at Cracked.