*You have a sales call to make and scroll through Facebook instead.
*You must hand in a report to your boss, and you waste time changing the font, moving sections around, and adding a logo instead.
Thinking things through and deciding what action to take can often be more exhausting than the actions themselves, so you procrastinate and avoid doing it.
When you're feeling good, you can plan to do the tasks you know you want to, but if you only have free time at the end of the day after work, exhaustion creeps in, and you lose motivation.