Sounds like you've got social problems from reading some of those.
Going out to a restaurant is more about socializing and enjoying yourself or celebrating occasions than actually eating the food.
I suppose there aren't many other ways to celebrate with a bunch people, even Jesus did it with his last supper. I just don't enjoy like everyone else.
If I want to spend time with one person I'd rather go for a drive or a long walk, or even go fishing instead of sitting in a big room eating.
Eating out is a big deal in the US I know lots of people who eat out once a week. I think it's almost a status symbol. Once a week at $50-100 (more if they have kids) x 52 weeks, that's thousands of $ a year literally flushed down the toilet.