Everything in service for others
Despite being intrinsically motivated, I know I benefit from external factors. The biggest one being other people. When I'm doing something for someone, I will be far more likely to accomplish it (no matter how much I want it for myself already. Throw others in the mix, and you can consider it done on my end).
We often hear "it's not about you." What do you mean it's not about me!? I'm doing the work, I'm creating the thing. How is it not about me!?
Because everything is easier when it's done in service for others.
Want to be in better shape? Find something that needs you to be in better shape, and you will get in better shape. Maybe that's why so many people run marathons for charities.
Want to learn a new skill? Find an endeavor or a job for someone else who needs that skill.
Want to get better at your current craft? Teach it, and you will be forced to always up your game for your students. Perform it, and you will be forced to grow your abilities for your audience.
It's okay to do things for you, but it might be better to do things for you and to do them for others. They're really one in the same.