When students don't like a teacher that means the teacher is doing their job. Is that mostly true?

My coworker (friend) works in the same preschool classroom I am and most kids don't like her. They won't even talk to her sometimes. She is mostly the disciplinary and too serious. I am too but some kids likes me. I don't care who doesn't like me. I just do my job too. She complained to me that kids don't say hi to her and don't respond to her. I told her, "Well that means you're doing your job." Not everyone will like you and some people won't like you for taking responsibility and being on them but so what? Keep doing your job." I heard this saying before.