Two that I can think of:

"Payback's a b1tch."


"Karma will get him/her."

I just shake my head. There are plenty of bad people in this world who never experience "payback", (b1tch or otherwise), for their evil deeds, and Karma never seems to bother them. Just stop saying's overused and you sound like an idiot from Jersey Shore or other such uneducated masses.