Why do we give so much importance to friends and social life during our teenage or as we grow up?

why does literally EVERYTHING in our teenage and college years come down to friends and social groups? Like seriously, I had this amazing group of friends in 11th-12th grade. Now I'm at a different college and can't seem to click with people the same way. And yeah, it kinda sucks, ik I should move on, but I can’t help being reminded of all the fun times I had (nostalgia is one hell of a drug). The weird part? Even when you have friends, you still want MORE social time. It's like this endless hunger for hanging out and connecting. When people talk about college memories, nobody's like "oh man, remember that awesome lecture?" It's always about the friends and fun times. And when you think about it - outside of career goals and stuff, what else is there besides relationships? Friends, family, social life... is this basically what life comes down to? Maybe I'm overthinking, but I genuinely want to know why we're wired this way. Why do we care so much about fitting in and having people around us?