If you feel like you don't belong, it's because you're not a part of a clique. TheFreeDictionary defines a clique as "exclusive group of friends or associates" and EtymOnline adds that a clique is "equivalent of 'claque'", which is defined as "band of subservient followers", meaning people distributed throughout the audience to clap enthusiastically and generate good vibes for the performer.
Cliques are supervised and managed by the owner, who shepherds people in the clique for his or her own pleasure, enjoyment and support. The owner sees the clique members as a resource that feeds his ego and will defend it as such. If you attempt to join a clique, you will be seen as an impostor or pretender trying to seize the resource, regardless of how wide of a smile you put on.
Clique members can even join forces to oust you from the environment or attack you, as if on command; they simply share an understanding and have a common mindset you don't share, otherwise you'd already be a part of the clique. If you happen to get cliqued and try to call the police, there's 5, 10 or more voices who will say you were the one trying to encroach on their space and the result is always the same – move along, buddy.
Cliques rule everything, from who will be invited to a birthday party to who goes with whom to a prom. The sooner you realize that without a clique you don't exist, the better. So, what do you do if you can't find a clique to call your own? Make one.
If you repeatedly find yourself rejected from all cliques, the problem is most likely that your power level is too high, as it were. You're simply too smart, too energetic and too forceful for an ordinary clique composed of ordinary people. So, recognize that cliques are everywhere, realize that you're not a part of any of them and move along until you find people as extraordinary as yourself.
Instead of struggling to be a part of a clique, which puts you in a subservient position, aim to become a clique owner. As soon as you do that, you'll have impostors and pretenders trying to elbow their way in, the same way you tried to when you were on the outside. Of course, you'll try to defend your clique members, since they are feeding your ego.
If you find yourself not belonging to any clique, it's because you are too extraordinary. Don't settle to be ordinary but aim for the extraordinary. Relish in your power level and enjoy the fact you're not there to sustain someone's ego but can actually make something of your own.