It's a weird situation, being the only person to be eating in a restaurant. I'm not talking about a fast-food place; I mean a real sit down ordinary restaurant.
There's a little Japanese restaurant in my town, and I went there one afternoon just after it opened, at noon. While this was on a weekday, and Japanese restaurants tend to attract business types, I sauntered in there in my usual t-shirt and jeans look (this place is very casual, so that's OK) and found that I had beaten all the white-collar folks. I was, in fact, the only one in the restaurant; probably their first customer of the day.
Things are different when you're the restaurant's only customer. While the service is exceptionally fast (and there's no reason for it not to be) it feels odd to be sitting there all by yourself. Restaurants are not one-person experiences; even if you sit by yourself, you can become comfortable in the ambiance of the place. At least, that's how I see it; YMMV. Also, it feels naked to be there all alone, and anything silly that happens can be traced back to you. Drop a glass? It's you. Mobile phone rings? You. And so forth. Fortunately, I was quiet during my visit, so no bad feelings were invoked.
Next time I go out to that place at noon, I'm bringing a friend.