U2
How would you like to be the guy that told U2 that they were "not suitable" for his label? That has to be right up there with the guy at Decca that took a pass on The Beatles. And both really happened.
Take a look at "Dear Bono" letter from RSO Records (the former home of the Bee Gees and Eric Clapton, among others) that cost the label untold millions of dollars:
Hard to belie