first experience with a computer that i can remember was XP. by golly was that the simplest OS to get into and just bang out a session of Club Penguin or random Flash games. looking at it now, it's so dated design-wise, but it was literally everything a casual internet user could need and then some. i never owned an XP computer myself however since my family was too poor to buy one back then, so i had to settle for mom's office PC and internet cafes. this is the most nostalgic/memorable to me because it was my childhood.
Windows 7 was the next experience for me (completely skipped Vista) and i loved it dearly as well. this was the OS we used for our first ever family computer back in 2012. Aero was so cool, but i had to constantly disable it and use the '98 theme to speed things up. our PC was that bad; it couldn't even run default Windows 7 by itself without having trouble lol. i skipped 8 too thankfully, as i was mostly using my phone and a Chromebook around the height of that one's popularity.
eventually i found myself first using Windows 10 on my gaming laptop that i got as a bday gift in 2018. the machine i was using was finally top of the line, and as a result my experience was finally relatively smooth. i became the most productive i've ever been, and it's translated to my own PC that i built and use right now.
most memorable change to me would have to be the start menu. it was literally perfect in XP and 7, unusable in 8, and went up to being "meh" in 10. always questioned why they needed to change something that, in my eyes, wasn't broken, but hey i've gotten used to the new one so far. can't wait for them to change it in the next iteration whoopee