It could be a bit like that elusive thing called motivation. "Just do it" seems so annoying when people say it but in my case sometimes its the only way to start building momentum. What im saying is dont wait for mood, perhaps the mood will develop once you obtain momentum on a goal or task.
Yeah I do hold this attitude and try to side brush "mood", which I believe is a mere suggestion, not a command. However I noticed a completely different "mode" when I'm operating IN project and BETWEEN projects.
When I'm IN project, "just do it" works very well. But when I'm BETWEEN projects (this is when I completed a project, and dived into the next project, but found out that I did not enjoy it or got lost or whatever), "just do it" only works when "just do it" -- it doesn't really create a focus needed to move the projects forward. What I got frustrated is that this IN BETWEEN period could take multiple months to get out, which is a super waste of time. If only I could figure out as soon as I completed the previous project, I'd achieve so much more -- you see, for the type of projects I'm working on, I could not afford to wait for several months, or even several weeks -- because this is not my daily job, so if I wait for too long I'm going to lose the knowledge -- it's like muscle training, you can't stop for several weeks and hope muscle retains.
I use the “just do it” trick a lot myself. It was something I discovered when I was in my early 20s, hiking the Appalachian Trail, which requires you to get up and move every day. My partner and I did not have much money, so if we failed to finish, we would not have a second chance. I remember waking up one morning after a rainstorm, realizing that I left my boots outside the tent. They were cold and wet. Putting them on was going to be unpleasant. I thought “I just need to do it so that I can have other things that I want in my life.” Something clicked in that moment. Now, whenever I don’t want to do something I ask “does it help me do or be what I want?” It helps a lot. From big goals (eg, earn a degree, get the job I want, etc) to little tasks (take out the garbage, clean the toilets, etc). Oddly I find the little jobs to be the hardest, probably because although I recognize that living in a house with clean toilets is something I want, it’s not obviously connected with a motivating goal. This mental trick is very helpful for the little tasks.