Great comparison between motivation and creativity, one of the best i can say. I find that really funny, cause people tend to stop when they do not feel like doing something like painting, cause you're the one that is pushing yourself to do what you do. Usually, the motivation comes to me when I start painting... rarely before that. I understood that in the middle of the last year and I abuse that fact since then.
I also have a bit of battle getting started. But once I push myself through the inertia, then I can't stop. Thus it is preferable that I start the day early, otherwise it means very late nights and terrible sleeping patterns. I also find the early starts far more productive.
Oh... The sleeping regimes. I find the night better for work, cause it's easier to isolate myself and work. But the day is better for doing work outside, meeting with people and socializing. Recently I feel like I'm more productive in the morning too. Not sure why. I've seen a lot of articles about the difference between working thru the day and the night. I prefer to work at night if I want to tunnel, and thru the day, if I have other tasks related to other people. My sleep regime is pure chaos, I try to establish a sleeping routine but it's not that easy cause of all the years playing games and studying in the late hours of the day.
I made an absolute mess of my sleep patterns a few years ago, so much so I did not see daylight. That really started to affect my outlook on things. It really requires mindfulness to institute the discipline with bed time. The time we actually get to bed is the key.
I just need more self-discipline cause my family suffers from that, they don't show it but... I guess that you know the look on their face when they see you tired, looking like zombie.