Personally, I think to feel that you have done enough for the day is mainly a focused decision by yourself to calm down and relax. Appreciate what you have done so far.

Especially when you are a very intellectual person and it's hard for you to stop your mind.

You will always find something what you could do more and so on. It's like when you always wanna be better and never appreciate the things you have reached or how you are right now.

Always a seeker.