Grow Up Already Ladies

I'm constantly amazed by people. So often I find myself shaking my head and just laughing. At what point in life do people mature? I ask this because while teaching dance I'm not at all surprised when I hear one of the kids say 'Oh, I don't like her'. They are kids and I can understand that coming from them. As for my friends, some of them are quite a bit younger then me and I still see that behaviour from them and I'm ok with it. I guess I figure they'll get over it as they get older. But yesterday I realized some people I associate with who are quite a bit older then me are truly still doing the 'Well, I just don't like her'. Sure there are people I feel that way about but in adult professional situations you have to act above that. You can't call a meeting and not invite someone just because you don't like them. Socially, it is different. If you don't enjoy someone, don't spend time with them. But professionally, its unacceptable and completely immature. This isn't exactly high school or is it?