Humans survived by exhibiting laziness behaviors

It helps conserve energy when prey was not available for hunting and plants were not plentiful to gather. Last action you want to do is run a marathon for fun when you don't know the next time food will be available to replenish.
The laziness behaviors help reserve the resource you do have until an opportunist time occurs to risk using more of limited resources for a chance of high-risk high reward prey or marketplace opportunity.