4. Andrew "Dice" Clay Is Banned for Life (1989)
It's hard to know what else the MTV brass was expecting when they put X-rated comedian Andrew "Dice" Clay on live TV for three minutes to introduce Cher. He went ahead and debuted two of his infamous "dirty nursery rhymes" (including "Rockabye baby on the treetop/Your mother's a whore, I ain't your pop") and said two of George Carlin's "seven dirty words you can never say on television" for good measure. The Diceman was banned from MTV after that night, and his career hasn't exactly thrived enough to give them any reason to reconsider. However he did reappear in a memorable sketch for the 1992 VMAs, making fun of the whole fiasco.