Are you being childish?

I was having a chat with my friend Jane and she was complaining about her new neighbor. She told me that the new guy is ridiculously childish and annoy her a lot. So I told her to minimize any social interaction with him, because, hey, life is too short to please someone else, right? She has other nice neighbors she and Mark can hang out with.

Talking about childish people today, I remember my own experience in 'childish-ness'. Actually I don't like to judge whether a person is childish or not and I always think that every people have their own reason to do anything. So how do you decide whether a person is being childish or not?
A person is being childish when they show no ability to stand in someone else's shoes and look at things with different perspective or imagine someone else's feeling in given situation, even when they already know all the facts behind it. They simply trample on everyone else's ideas, thoughts, and feelings, without regard. Their ignorance is usually apparent, so simple avoidance is often a useful tactic. Sometimes they even accuse us of being the childish one.

So are you being childish towards other people? Or simply doesn't care whether someone else thought of you as a childish person? During a complicated situation, I chose the second one, because I know I am more mature than a person who easily judge other human being with such awful accusation.