Nicki Minaj
Nicki once demanded that the lawn around the venue be cut evenly or she wouldn't show up for the concert. She was close to an hour late because she thought that "since the grass was cut unevenly it was hard for her to walk on, so she didn't." Talk about a serious diva move!
Jessica Simpson
Simpson was once invited onto The Tonight Show with Jay Leno, was declined last minute, and never was invited back. The reason she got her slot canceled was that she requested $18,000 for her hair and makeup team, firmly. Leno told her to pound sand, and they had Sarah Palin on instead of her.