I'm intrinsically motivated. Work flows into my day, and I usually mildly enjoy whatever I do. I generally don't schedule for anything to happen, and do whatever holds my interest in the moment.
This is a delicate process. Intrinsic motivation and interest can be crushed with sufficient pressure, even if temporarily. If money or assignments or any other extrinsic factors weigh too heavily, it's going to be way less fun and way harder to do any work.
A key take-away is that if I want to start doing more work in an area, I have to get emotionally invested, interested and curious. Sheer willpower has not worked in my past experience.
This also means that it's hard to force myself to do anything I don't enjoy. This should probably factor into what I choose as a job.