What does it mean to grow up?

I’ve said in other threads that I think every generation feels like society is going downhill, that things were better in the past, and that I think we are all wrong about that, for the most part. So now I’m going to say that in one particular area, maybe it’s true. It seems to me that there are an awful lot of middle aged adults who continue to behave like teenagers. I don’t want to give a lot of examples and start arguments (although I’ll likely weigh in at some point and grind somebody’s gears). So in general terms, I think of growing up as learning how to prioritize, respect people, put your family above yourself, and to behave in a manner that considers the impacts of your actions on others. What do you think growing up means, and do people tend to not grow up anymore? Is this a good or a bad thing?