Writers, what makes you like a character?

What I hate the most is when the character is perfect. Writers think they can make the character not have a single flaw, and I hate it. There needs to be something wrong with them. I also hate it when the character is always GOOD. The character doesn't have to be evil, but they need to be mean SOMETIME. In most books where the character is perfect, I find myself rooting for the opposite team, the bad guys. I never figured out why I hate perfect characters, but I do.