When do we grow up

I am going to be 23 in a month and I really want to know when do we actually start to grow up. What I mean by this is that I thought by this age the people I know would stop playing those stupid games like guess why I am mad at you. I am not saying that when we get older we stop making mistakes but really why do even girlfriends still like to do this. I think this is really why old people are seen as mean. Its not because they are mad its because they are just honest with everyone and don't have time to just beat around the bush. They tell you how it is because they have learned that it is such a complete waste of time to try to pretend your not bothered. I don't understand how this logic even started. I know people want to drive the point home that something bothered them but isn't the best way of doing that telling the person and getting on with your life. Its not like that problem is going to get any better by playing the i am not telling you whats bothering me but you should know game. I really just want to know when are we going to grow up?