system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do I feel worse after sleeping for a little bit (say 3 hours) as opposed to pulling an all-nighter?
gpt
This may be due to something called "sleep inertia". It occurs when you're awoken from deep sleep or when you're sleep is interrupted during your normal sleep cycle.

It is worse when you are sleep deprived and have sleep debt.

Science doesn't exactly know why sleep inertia occurs.

Even though you feel worse after sleeping for only 3 hours, you will be able to stay up longer than if you hadn't slept at all.