People who keep a meticulous mental cardfile of every way they've ever been wronged in their life so that "one day" when they get rich and famous they're going to make every one of those fuckers pay. Preferably by getting their toadies to do all their heinous dirty work for them so they can conveniently disavow them later. Thankfully they make no secret of the fact that they just view everyone around them a stepping stone to their personal happiness or an obstacle in their path, so they never have any real friends or income for long...
Either learn to let petty shit go, or you're going to turn into Chris Chan...