I have only rarely have felt this from programming (at work or not). But as a competitive chess player, I do usually experience it at the end of (especially) w

I have only rarely have felt this from programming (at work or not). But as a competitive chess player, I do usually experience it at the end of (especially) weekend tournaments, where there is generally 3 consecutive days of 8-10 hours of intense concentration. The fog is gone after a good sleep and day of rest.