Usually they don't like someone because they are poor performers. As a person who has owned a business with employees, you naturally like the ones that are making you money. In fact, I'd put up with a whole lot of things I don't like if they make money for me.

As a manager, I'd naturally want to retain the people who made me look good to my manager, regardless of my personal feelings.

Having a personal vendetta against particular employees has never happened in my experience, though it's been alleged a lot.