Honestly bro, there's no point sometimes. There are some people in the world who, no matter how much you want them to, will never be able to recognize when they're wrong. If these people seem that way, then the best way to deal with them is to either kill them with kindness, take it in stride, or just remove them from your vicinity altogether. 

Stewing over it will only serve to upset you; if you are just basically decent to them and encourage no further conflict, you'll both be rid of them and show everyone else that you're the bigger person ^_^