I personally don't find that being around others is very restful. At work or social gatherings, I'm not always involved in the conversation but there is a chance I could be so I end up listening. And other times, I could be completely alone and my mind wanders. My mind like yours is always thinking. I don't find that very restful.
I think for me, reading an article/comic book or watching an interesting video is restful.
I was thinking yoga or meditation are probably really good methods of rest.
Great comment. One thing I believe is worth mentioning is that even if a person practices to find this "tiny thing" in their heads and fix it, they may not find it for a very long time. Some people can practice something for decades and still not be professional with whatever they are doing. They could also figure one "tiny thing" out but their may be many more "tiny things" to uncover after that.
I personally wouldn't have school projects if you have been out for two years. I'd have personal projects you have worked on in your spare time. I think these are much more interesting to see.
Probably isn't difficult once you get started and have goals set in place to do so. I'm only in my early 20's I haven't even thought about retirement. However, I am saving all my money at the moment. Hopefully that helps me out later when I really need it.
Senior developer is just very difficult to define. You could define it based on the amount of time worked at a certain job, your skills, your ability to mentor. The definition could be different for various businesses and their employees.