nostalgia is the happysad feels you get when something in the present remembers you of something in the past.
it works with memory. your brain has little boxes full of memories. each box has a time and a date on it. you cannot see inside the boxes but your brain can.
sometimes what you can see or hear or touch or smell or taste reminds your brain of something that you saw or heard or touched or smelled or tasted in the past. then your brain will go to that memory box and open it and stick its tongue inside to make sure it's just right and then it will drink the contents of the box and then it will vomit those memories all over your face. then you feel happysad.
you feel it because you never forget.
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