eli5: Why do we always get strong urge to be lazy if its better for the brain to be active

Question

I mean its so much better for the brain to be active working doing useful things stimulating your brain or working out, we all have a reward system and everytime we finish a task we feel a sense of accomplishment but everytime you should be doing something that you know will feel good in the end you just get this urge of doing nothing today and just relaxing,
shouldnt our brain be chasing this sense of accomplishment? Where does this feeling come from

In: 7156

Answer 1

Here is the non-theoretical, non-theory-of-evolution practical scientific answer as explained to a 5 year old:

Within the context of being lazy I assume you’re talking about watching TV, playing video games, scrolling endlessly through feeds on your phone etc – your brain releases a chemical called dopamine, and it feels good so you want to do it a lot.