Video Evidence: Paris Hilton, 2011

Even sex-tape peddling reality stars are competitive. When Dan Harris asked Paris Hilton if she worried about the Kardashians and other upstart reality stars eclipsing her, she was not having it. After a few brief non-answers, Hilton stormed off the set. Though she would later return with some well-rehearsed answers, the damage was done, and we learned that even reality shows that aren't Survivor or The Biggest Loser can be a competition.