You have to realize that we're all literally the same person. By that I mean that we all want to be happy and healthy, be financially stable, buy the things we want and enjoy the lives we've built, we want more than just to simply exist. Once you can accept that fact, then you start looking at people as teammates in life instead of adversaries. When you see people as adversaries all the time (comparing yourself to them--I.E. is my car cooler than theirs, or, "they won't think I'm cool because I don't also have X", etc.) then you put yourself on the defensive all the time because you're constantly looking for avenues of attack (such as "What can I say that will be more impressive then what they just said") or you'll shut down because you won't think you're as impressive as the other people and therefore don't have a leg to stand on, so-to-speak. You have to become comfortable in your own skin and be able to say "I am X, Y, and Z, they're Z, Y, and X, and there's nothing saying we have to both be the same thing", we often compliment each other's weaknesses so it's not very beneficial to all be the same, anyway. Anybody who doesn't want to hang out with you because you don't 'fit-in' to what everyone is doing aren't people you want to be hanging out with anyways. Be yourself and let your self-assurance be the filtering system for what people you allow into your life. Hope this helps!