Why would anyone do that? Maybe a masochist, but not a normal person. I feel mostly indifferent to people who hate me. And I pity them for harboring that emotion. Hate is an anchor, it'll drown them.
And honestly, love can be an anchor too, with the same results. Loving to change someone is a waste of time and energy, and wastes precious time of two people's lives.
Love to be true love must be a circle. It must be given, received and given back. Otherwise it turns rancid.
You only get one life. They get theirs you get yours. I always hate it when people say they wouldn't want their spouse to date again if they died, or split. Since when should anyone sacrifice their life for anothers wish? Who on this earth believes their life has the value of two lives, their and someone elses. What terrible regrets would come when on your death bed you looked back and thought, I stopped living to please someone else.