If there is something that I learned from my daily struggle with procrastination, is that every day you just have a limited amount of decisions. Every day, you can only do 5, 8, maybe 10 meaningfully decisions. After that you will start doing mistakes, get tired and, in general, doing wrong.
What can be surprising of this, is that doesn’t matter how important the decision is. Look at a traditional day: you wake up and you need to decide what to eat for breakfast, what clothes to wear, if it is better to go to work using the car or public transportation. You have literally just waked up and you have already depleted the big part of you decision pool for the day. And none of that decision is meaningful for your work, your career, your family, your affections.