"The thought of his being president sends a cold chill down my spine," Cochran said about McCain by phone. "He is erratic. He is hotheaded. He loses his temper and he worries me."
McCain's run-ins with other Republican senators are legendary. Senator Charles Grassley of Iowa said in an interview that he was so upset by a McCain tirade that he didn't speak to him for two years. Grassley, who said he will make no endorsement, nonetheless says McCain is the most qualified among the five GOP candidates to be president.
Here is a list from a conservative site listing McCain's top ten temper explosions.