Ignored.

People say they like to "include everyone". As in they don't want to sound ignorant. They want to be "all accepting".
"Mentally challenged people should get more attention!" they all say.
"Look at those poor starving children in Africa!"
"Racism and sexism should stop!"
"Everyone should not bully and be nice!"
...
Yes, that is all true. Yes, those are all minorities. No, they do not deserve to go unnoticed. But the truth is, they don't go unnoticed.

Socially awkward people are not considered a "minority". Why? Because there is not physical problem with them. They simply don't know how to act in social situations.
This may have something to do with their upbringing, or it may have something to do with not being noticed from the very beginning of their social life.
Since they aren't skilled in interacting with others, people stay away from them. They're "weird". They're not like the others. They are excluded. And that hurts.
Now, in some cases, this person may be fine. They don't care for social interaction. But in other cases, these people want to be loved and noticed. They try to do what they have to do to get this. These people love receiving attention from others.

Now, if they've succeeded in gaining the attention and respect from others, then they must maintain their social status. Any slip up could completely ruin their social life.
But for those who haven't succeeded, they may become upset. All they want is for people to notice them. I believe this is where "emo" teenagers come from. Another type of person may emerge from this too. The "crazy" ones. Oh yes.

Social anxiety stems from being ignored in social situations. They cannot come up for a reason why they are ignored, so they blame themselves for being too "weird" for people to like them.
Sometimes, other people who don't get noticed just... "Snap". They go crazy from lack of attention. That's just how their brains work.
Who knows why we split up in to these extremely exclusive groups. Maybe it could be because of... Respect?

That was a lot of quotation marks.