As I'm writing this, I am irritated. I am irritated at the way people treat others, and I am more irritated at the fact it even has to be addressed, Listen, I get it. I know that there are people in this world that are going to drive you crazy. There are people in this world that you aren't going to like, and they aren't going to like you. But this gives you absolutely no right to treat people like they don't deserve respect. Just imagine what kind of world we would live in if girls didn't go out of their way to be catty, and kindness was more apparent than pettiness.
Listen up, you are not better than anyone. People have different interests and we are all raised differently. You may not agree with the way someone lives, but guess what? It's their life and not yours. If you disagree with it to a point where it seriously bothers you, then you really need to take a step back and realize what's important in life. Everyone's parents has a different style of parenting. Some people may have less manners than you, some may even have a lot more than you. Some people may believe in things that you don't believe in, but you need to understand that our differences is what makes life beautiful. God gave each and every one of us our own special unique characteristics that make us who we are. You have no right to talk down on anyone if God loves us all the same.
Like I said, there are going to be people in this world that you don't like. It's probably going to really get to you at some point in time too, but you know what the best thing to do is when you don't get along with someone? Ignore them. It's pretty simple. Let them live the life they want to live and let them do it happily, because odds are, they don't care what you think.
No one is going to change to be the person you want them to be and you have no right to try to mold anyone to your standards. You have no right to talk about someone without knowing their full circumstance. You have no right to exclude people for not being in the same group as you. Do you get what I'm saying here? If we all came to realize that everyone is different and grew to accept those differences, I bet this world would have a lot less animosity.