I've noticed this when playing chess, which is I guess a pretty good way to measure one's analytical capabilities and concentration. When playing against a comp

I've noticed this when playing chess, which is I guess a pretty good way to measure one's analytical capabilities and concentration. When playing against a computer in the evening after 8+ hours of work my games are significantly weaker; I can't anymore beat the same game level that I easily win in the morning. By looking into game stats I've noticed that in the evenings I make significantly more mistakes, don't see good moves, make hasty decisions more often, etc.