system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why everything is funny when I'm tired.

When I am tired, everything is funny. Not 10:30 tired, 3:00 tired.
gpt
When you're that tired, part of your brain goes on vacation. Specifically, your frontal lobe (the part in charge of keeping you calm and making you think through things) is just plain tired of keeping you in line. Therefore, you get fewer signals inhibiting laughter or humor.