Sometimes, you remember that Hollywood stars are famous because they're really, ridiculously good at acting—and that those skills might sometimes cover up the fact that they're actually hee-haw jerks who walk the planet only to make misery. Here are a few seemingly nice celebrities who might actually be awful.   

1. Katherine Heigl

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There are a number of videos of Katherine Heigl denying allegations that she's impossible to work with, like "Katherine Heigl On Being Labeled A Diva," or "Katherine Heigl on Shonda Rhimes' Negative Comments: 'I'm Sorry That She Feels That Way.'

But how could such a delightful personality have reportedly sandbagged Grey's Anatomy by pulling herself from Emmy contention and saying, "I did not feel that I was given the material this season to warrant an Emmy nomination and in an effort to maintain the integrity of the academy organization, I withdrew my name from contention"? Or caused "desperately difficult situations" that a source in the Hollywood Reporter recalled, including "wardrobe issues, not getting out of the trailer, [and] questioning the script every single day"?