I haven't experienced many, but there have definitely been a few.
-Walking into a building where you haven't been for years and it seeming so much smaller than you remember it.
-Going through old things and remembering what it was like at that time in your life
-Standing in a beautiful forest, with the line shining down and a small creek winding around, and knowing that through these trees, not so far away, is an abandoned building and the bustle of a city-like town
-Being face-to-face with a friend you haven't talked to in years, and you have no idea why you two haven't talked
-Actually being pleased with something you just drew/wrote
-That feeling when you change your look drastically (Cutting off a lot of hair, dying hair, changing style, etc.)
-Taking a moment to just enjoy nature, or at least what little you can see of it
-Staring up at the sky and seeing so many more stars than you can count
-Realizing you love someone
O THAT WAS MORE THAN A FEW UMMMMMMMMMMMMMMMMMM SORRY I LIIIEEED