I wonder what hobbies others have?

I like hobbies where I get a feeling of improving at something worthwhile, and that make me feel more confident. Some of my favourites at the moment are swimming, language learning and going to new places.

Some things I'm interesting in trying are acting, indoor climbing and possibly martial arts. I am doubtful about martial arts because it seems to me that you either take it casually and don't learn practical self-defence or you take it seriously and mix with aggressive people and probably get hurt. It would be confidence boosting to be proficient at self-defence though.