Your brain gets tired; Your body gets tired. When you push and push, You sometimes get LESS done!
This is so true, especially when we are really focus on accomplish something, is very important for us to be aware about the importance of get recovered, not only in body but especially in mind, it is a situation I have trapped myself several times, work nonstop with something in order to accomplish my goal until I get a mental exhaustion and end up wasting much more time recovering from it, than if I had have some regular smaller mental recover.