Personal Space, Please!

Personal space, anyone? Why do strangers feel the need to stand or sit so close to you on the bus that they are actually touching you? And what is wrong with those people who try to squeeze their two-foot body into a six-inch space at the bar, and then LEAN on you for the rest of the night, as if you were a pillar or something? The most frustrating thing of all is the fact that it doesn't seem to bother THEM at all. Yuck.