The last time I can remember a full on hate fest towards someone was with Lea Michele in the first season or two on Glee. Everyone talked about how much trouble she was and what a diva she is and no one had anything good to say about her. Has she changed? A little. You will notice she doesn't get many roles outside of Glee because of her reputation.
In a new article in The Hollywood Reporter, Katherine Heigl is trashed as the worst person in Hollywood to work with and that the only person more nasty than Katherine is her mother who has been Katherine's manager forever and judging by the styles that Katherine wears, also the biggest lender of clothes to Katherine.
No one had good things to say about Katherine on any movie or television she where she has worked and that she lost the chance at a television pilot this year that she would have been perfect for simply because she wasn't worth all the trouble. Think about all the people out there willing to work who are nice and easy to work with and on the same level of acting and it's pretty easy to see how you can go from millions to nothing in a second.
She is very nice to dogs though, and adopts kids.