I've always been black and white like that. Once I get everything done, then I can do this. That kind of thinking usually results in a lot of stress, unhappiness, and being unproductive. I always forget that it's progress, not perfection.
When I was in therapy, I learned a few important things on the subject. I learned that people don't tend to continue doing anything unless they derive some sort of pleasure from it. This is why it's important for people who are depressed to find things to do that they enjoy to help get them out of their rut, rather than try and try in vain to develop habits that, though would improve their lives, they derive no pleasure from. The results have to be instant, or there's nothing to hold their interest long term.
And one good way to do this is to follow the 'Pleasure Before Mastery' rule. This rule means that instead of doing something masterful (something effective, responsible, dutiful, that sort of thing) and then rewarding yourself with something pleasurable like relaxing or indulging in a hobby you enjoy, you should do it the other way around: you should do something pleasurable and then do something masterful.
It might not make a lot of sense, but when you think about it, aren't you in a much better mood, perhaps more energetic and fulfilled after doing something for yourself? Something that feeds your soul, replenishes you and, in turn, makes you a more productive person. If you get the "fun" out of the way, you're much more likely to get more things done than if you were to with-hold pleasurable activities till your to-do list is done.
I have tried this and can say it does work. I know a lot of people would think it's silly to do things this way, but those people probably value doing rather than being, and that's fine for them. For me, life is not about to-do lists but I certainly do a wonderful job of making it about that.
I dare you to try this. I'm going to take my own advice and make sure I start my day with at least one pleasurable activity. Then, I will be all responsible and stuff :-) I do not want to die knowing I wasted my life on a perpetual to do list, waiting for it's completion to actually live. I am tired of being in a state of preparation. I've spent way too much of my life waiting to live it.