18. Prince

The “Purple Rain” singer’s biggest request came in 2007, when he asked the owner of the O2 Arena in London to build him a swanky five-bedroom home near the venue he was to perform in. In 2004, he demanded that items in his dressing room must be covered in clear plastic wrap, which only he was allowed to remove. He also made it clear that a physician must be backstage at all times to give him a booster shot of vitamin B12 before each show. He isn’t called Prince for nothing.