Not liking everybody or desiring solitude or preferring one close friend to a group of many is not social dysfunction. We're overgeneralizing what it means to be "anti-social" or "socially anxious," when those are extreme, if not clinical terms that we may want to think twice before throwing around. Here, a few ways to determine whether or not your social sensitivity is normal:
1. You experience a degree of social anxiety in unfamiliar situations.
Social anxiety is usually having enough foresight to recognize what people may be judging or assuming about you. If not kept in check, it can paralyze rather than keep you self-aware. It is normal, if not indicative of a high intelligence.
2. You desire solitude because being alone is emotionally enriching.
You do not isolate yourself when you'd prefer to be with others, simply because you're afraid or feel unworthy of keeping company.
3. You only enjoy the company of a few, select people.
You're not supposed to like everybody. To say that you "like everybody" would be to deny and reject the parts of you that may not genuinely feel that way, and as we all know, disassociation isn't good. We're only meant to really love and enjoy a few people, and tolerate a few more.
4. You say no to plans when you want to say no to plans.
You do not go because you feel obligated or pressured. You are able to say "no" to people who you don't want to see, and to doing things you don't really want to do, when the cost would be your mental or emotional well-being.
5. You analyze situations because your snap judgments may not be well-informed, not because you'd like to reinforce your anxiety or make yourself feel better through delusion.
You self-evaluate as a means of becoming aware of what (may, perhaps) be unconscious choices and habits. You do not over-evaluate with the intention of arriving at a different, made up conclusion, or to create an alternative perspective that supports an irrational idea: "He looked at me funny, I knew he hated me."
6. You worry that your social anxiety is abnormal.
Worrying about whether or not you have too much anxiety about being in social situations is probably the most normal thing there is. That's not a product of "having a severe problem," it's a product of wanting to be self-aware enough to handle it if there is.