All thru his life my dad was passionate about (1) hunting (which he did a lot of and when not doing it was reading about it and studying pretty much every single day) and (2) horses (which he rode nearly every day). Until the day he passed away those 2 hobbies where his hobbies, stuff he dreamed about and never got tired of. I havent found that (cue U2, I still havent found what I'm looking for music)
But regardless of your hobby is it something you think about daily, and scheming how to do more of it and excited about it?