Define "sociable."
Just being in the same room with a group of people doesn't mean you're socializing, even though they may be. I got along with most of the people I worked with and could chat a bit and make jokes with them, but I still spent 98% of my time in a closed room, working by myself.
In the High School where I graduated, everybody knew who I was, because it was a small town and my dad's job was fairly prominent. Nobody had a particular reason to dislike me (because I kept to myself and didn't offend anyone). To this day they choose to remember me as just another part of their peer group.
What they don't seem to remember is I sat in the back of every class, hiding behind a curtain of hair, drawing or reading a book and most of them never said two words to me the whole time we attended school together. There were maybe a half dozen people in the entire school who ever went out of their way to be nice to me and the rest of them ignored me like I was invisible (and for all practical purposes, I was). The kids in the youth group at my dad's church were more friendly to me there, but even they hardly spoke to me at school.
Its funny how selectively people perceive things like that. They may think of you as having been "shy" or "standoffish," but really have no idea just how isolated you actually are, because they're so busy talking and socializing themselves, they just don't see it.
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"I don't mean to sound bitter, cynical or cruel - but I am, so that's how it comes out." - Bill Hicks