What would you say is your "primary" hobby? The activity or field that you've spent the largest portion of your life thinking and learning about?

For me, if would definitely be retro gaming. I'm the kind of guy who can tell what system a pre-2001 game is on just from a screenshot, visits /vr/ constantly, and thinks the video game industry shouldn't have progressed past the Dreamcast. I just love learning about these little historical tidbits and playing through games that impacted the lives of people decades before my time.