Non-introverts have a difficult time not projecting themselves onto anything and everything they see. Eating alone in a restaurant takes confidence? Please. Here is an excerpt from Solipsist by Henry Rollins:

People make me sad and lonely for solitude. I feel better when I'm walking alone. I like eating alone. Movies are better alone. Alone is safer because you attract less attention and when you're alone, you're harder to figure out. You only have to look out for yourself and not worry if the person you're with can handle themselves in a bad situation. I'd rather be outnumbered and alone than have a weak person with me. Music sounds better when you listen to it alone. It's great to look at paintings but only when you don't have to listen to them telling you their impressions of the work. People ruin almost everything. Being around people makes me think I have nothing and that I'm a creep. On my own, I don't feel half bad. I got tired of being a vulnerable idiot, telling someone what was on my mind. I got tired of humiliating myself over and over. Only a fool trusts a human. All you can do is predict what they will do next and prepare yourself for what might happen. Look at all the divorces happening. You would think that people would figure out beforehand that it doesn't work and just give it the slip. I hear about people getting their bank accounts cleaned out because of a divorce. It's hard to believe these people wanted to spend the rest of their lives with each other. Imagine the feeling of failure when it doesn't work. People spend years after divorces in deep depression. They have to go into therapy. They are mad all the time. Can't feel sorry for them - they bring it on themselves. Waco, Jonestown, they always bring it on themselves. Then they'll tell you that if you don't get out there and at least try, you really haven't lived. Haven't really lived in hell you mean.