You know you're an outside amongst a group of old, old friends when one of them says something that sounds completely out of context and everyone else bursts out laughing.
"And I was like ohmygod stiletto!"
We all do it. We all have silly phrases/words/noises/actions that are deeply context-based and were, at the time, hilarious/memorable/ridiculous. I'm not saying this is a bad thing. But maybe you should think about how they might make an outsider feel - exactly that, an outsider.
Not that I'm speaking from experience. Not at all.