Bad beats are never 50% or more to win. They should be very rare. However, I have seen many and taken many. NL hold'em: I'll tell you what though, I (finally) rivered someone with 2 outs. First 4 cards are 3 3 3 8. I go all in with 9 8o. Everyone folds but the guy behind me, who calls. He has an A 8. So, it looks like a split until I catch the 9 on the river and make a silightly higher full boat. And even worse, the next hand he goes all in with pocket Qs b4 the flop short stacked and someone calls him with A 3 off and catches the A, busting him out. I've had my run of bad luck, but I don't know if it has ever been that bad.