@jasty When in Rome, do as the Romans do. The world is full of unnecessary shit because people can't follow this simple rule. It doesn't mean you couldn't bring good things with you when going to a new place; we wouldn't have delicious ethnic foods available all over the world otherwise. But aside from such obvious, harmless things, it would make the world a whole lot more peaceful.
@Kaarme - definitely this. People who degrade manners and courtesy and differences between cultures are suddenly shocked when they're treated as unwelcome and obnoxious.