I have learned that not everyone will chose to "grow up". The examples that I could give of this situation are astounding. I have learned that it is definitely a concious choice (unless, of course, you are unwillingly forced into adulthood by circumstances beyond your control).
When encountering such individuals, I have simply chosen to take the high road and let it be, because if they refuse to grow up then they are also refusing to change no matter how much you want them to.
To grow as a person must be done in your own time.
If your refusal to change is negatively affecting others, maybe it's time to consider it.
By growing up, I don't mean becoming a stuffy, boring person. I mean maturing. Taking resposibility in situations that you have put yourself in.
Choosing to "let things be" is part of my #selfcare, which will be my personal theme for 2013.