I disagree, if someone is worth my hate I will never be anything like them. But there is a saying something like: He who slays monsters should take care not to become one.
My mom use too tell me this shit all the time. She'd drive me crazy with her " ways" and then would always tell me" Just wait, someday you'll be just like me".
Christ, I scream that I'd never be like her...Guess what? In many ways ...I AM HER!
I have never hated anyone. That is a very strong emotion to waste on someone of no importance. If I feel a strong dislike for someone that could turn to hate I just keep that person out of my life. Why give someone I dislike that kind of control over me?