Why do a lot of people hate Tiffany from Girls' Generation (snsd)?

I've come to like the K-Pop group, and I started to look them up. I was sad to see that they are very disliked by a vast group or people, but even worse the one I liked and recognized most (Tiffany) seems to especially get some heat. A lot of what I found on these things are forums, which is just a bunch of people arguing mindlessly. Could someone tell me some of the things she did or give me some articles? I really want honest answers please.