Britney Spears

To be fair, Brit hasn't been *all there* for a while, and we feel for her, really. But rumors of her rude behavior are totally unacceptable. Reports say she tipped nada on a $250 meal in L.A., and once even threw change at a valet's feet, saying, "There's your tip." Let's hope she's doing better in that aspect of life as well.
[Photo via @britneyspears]