It depends on what you're talking about. Are you talking about that "like OMG can you believe (some random ***** you've never met) kissed (some random dildo you don't give a shit about) even though he's going out with (some girl who you only know because she never shuts up)" social clique crap, or are you talking about like, dumb jokes and shit. Because I've heard the word "immature" thrown around a lot, and there's a difference between being mature and having a stick up your ass. As long as it's not something that's overall mean spirited and pointless there's nothing wrong with having a bit of fun, just as long as you know how to get serious when you have to. But if you're talking about the former, then yes, I understand completely.