In life, you will meet many, many people. It is unlikely that you will be able to get along with all those people. It is more than likely that you will have a not-so-good relationship with a lot of them.
You do not have to be their friend, but it’ll be in your best interest to at least be civil to them.
There’s a popular misconception that being nice to the person you dislike is the characteristic of someone who is two faced, who is “fake”.
If we were to be mean to everyone we didn’t like, the world would be even more full of anger and hatred than it already is. Kindness, generosity, and honesty would be qualities only described in fiction.
There’s no need to make a big deal out of not liking somebody. Really, nobody is expecting you to get along with everyone. We’re all human, our personalities clash sometimes, it’s okay. But for the sake of a well-functioning society, at least be decent to them.
Be honest, but not unkind. Be helpful, but not over the top. Don’t say anything you don’t really mean and don’t say anything that isn’t necessary.
If you dislike the person enough that being around them is hard for you, it’ll be better to stay out of their way than to spend time in their presence and potentially anger yourself and them.
There is a difference between being nice and being two faced. Being overly enthusiastic about wanting to talk to someone you don’t like is being two faced. Replying civilly to something they say and/or including them in a group conversation is being nice.
Recognizing the difference between these two terms is essential to realizing the type of person you want to be.