Validation.
The things which connect us are those things which seem so inexplicably important - like senior prom, or walking at graduation - things which many regret if they haven't done them (I am here speaking in reference to American culture, I realize that is by no means all of you and don't feel I'm leaving you out or over generalizing if this doesn't include you) not because they are in and of themselves so very enjoyable or exciting, but because... You just have to. And WHY do you "just have to"? Why are they so important? - because they are things which "everyone else" has done, they are those very few things which you share in common with the majority of the rest of your culture. There is comfort in a shared experience.
And as important as those experiences are we are also simultaneously searching for those things which set us apart, places we've been where few others have been, things we've seen that few others have seen, information we know that few others know... As an example: I've always felt a strange sense of pride at my incredibly bad eyesight. Really it's a bad thing, it's made certain aspects of my life a good deal more difficult, but I have always felt a strangely happy swelling in my chest when someone tries on my glasses and goes "wow! You're eyes ARE bad!" why? I know hardly anyone else with as bad of eyes as I have. Call me crazy but I don't think this is actually that strange of a feeling. There is thrill in a unique experience.
It's difficult to say which holds the greater weight, the thrill or the comfort, maybe it's different for each person, but on some level I think we really all desire them both.
Interestingly it would seem to me that each of these seemingly opposite experiences is sought for the same essential reason - validation. The validation of being unique and the validation of being normal. I'm not sure there's anything wrong with this desire for validation. In fact I'm pretty sure it stems back to our desire for God. I don't think there's anything wrong with wanting to be normal and also wanting to be unique - I just thought it was interesting is all.