Shoplifting, umbrella attacks, and catfights -- oh my! Ryan Seacrest won the Teen Choice Award for best onscreen hissy fit for his role in Knocked Up. But sadly, hissy fits and meltdowns are a real-life (and sometimes regular) occurrence for stars! Like Britney Spears, for example: The girl has been in one tabloid after another for her unpredictable flare-ups. But she's not alone -- keep clicking for more famous breakdowns, and vote for the worst.

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