It’s changed over time and will probably keep changing.

When I first started off in high school, I was primarily driven to get stronger for sports I played at the time i.e. (American) football and tennis. In college, my drive was mainly for vain reasons. I liked the way weightlifting made me look and that brought confidence in myself. After college, the vanity aspect was still there but I also started really getting into Olympic weightlifting and powerlifting, so that pushed me to get stronger in cleans, snatches, squats, etc. Now that I’m a parent, my drive is mostly to push off the “dad bod” stereotype from happening and making sure I stay physically fit enough to keep up with my kid, who’s relentless and won’t stay still. I’d love to be able to hit the gym with him once he’s a bit older.

Besides from these things that drove me, like others have said, it really just became a habit and part of my daily routine.