[troebr]

That's a robot's take. You can have days where you slept poorly or need a nap to get back on track or just lack motivation.

Personally I try to take on tasks that don't require as much brainpower. If I'm really too tired I'll just take a nap, because it's better to take a 20 minute nap and do work for the rest of the afternoon than feeling terrible and doing hardly anything for a whole afternoon.