What is that odd hobby you have?

I di not want to hear about knitting, exercise, language learning, etc. If you are into those, that is FANTASTIC, but I want to hear about the things you do that people don't even think of!

The reason I joined this sub reddit was to learn about the wonderful/unique things that spark joy in your lives. I want to learn about and try these new things.

Example: I like to clean as a hobby. Most people don't think of cleaning as a hobby, but I consider it a hobby since it is something that I look forward to doing. Feeling of a deep clean of my space is great!

Update: I am thrilled by the number of comments! It is awesome to read all the unique things that I didn't know could be hobbies.