Reading (duh), writing (theoretically), pens, flags, music (alternative, electronic, and classical mostly. K- and J-pop also welcome), languages and scripts, spaaace, anime, assorted fandoms. I can feel myself becoming a railfan and I'm scared.
As someone who is not particularly good at music in general, taking that tune I found on the piano and transcribing it onto sheets in such a manner that it does what I want is incredibly frustrating.