it is (probably) related to how long it took, you’re probably waking up mid-sleep cycle, when you do your brain has to wake itself up from deep sleep and that takes a while. best naps are either shorter than 30min (so you don’t leave light sleep stage) or around 90min (so you get a full sleep cycle in). when you wake up at the beginning or the end of a sleep cycle you feel refreshed and good- but when you wake up in the middle… “what? what time us it? who am i?”
it is (probably) related to how long it took, you’re probably waking up mid-sleep cycle, when you do your brain has to wake itself up from deep sleep and that takes a while. best naps are either shorter than 30min (so you don’t leave light sleep stage) or around 90min (so you get a full sleep cycle in). when you wake up at the beginning or the end of a sleep cycle you feel refreshed and good- but when you wake up in the middle… “what? what time us it? who am i?”
And they could just straight-up be dehydrated since most people are slightly dehydrated, anyway.