John McCain's temper is well documented. He's called opponents and colleagues "shitheads," "assholes" and in at least one case "a fucking jerk."
But that is not the most incredible story circulating "out there."
In his 1992 Senate bid, McCain was joined on the campaign trail by his wife, Cindy, as well as campaign aide Doug Cole and consultant Wes Gullett. At one point, Cindy playfully twirled McCain's hair and said, "You're getting a little thin up there." McCain's face reddened, and he responded, "At least I don't plaster on the makeup like a trollop, you cunt." McCain's excuse was that it had been a long day. If elected president of the United States, McCain would have many long days.
Also check out http://www.huffingtonpost.com/2008/05/01/mccain-asked-did-you-call_n_99744.html.