In WW: can't remember, it's so long ago but I sure did reset that game more than one
In NL: not that I can remember
In NH: never. I put so much work into this island that even if the river mouths are not perfect and the town hall close to the airport I could never muster up the motivation to start from scratch after being 300 hours in.
As for leaving the game without saving: I did that sooo many times in all the games less in NH, but in WW and NL it happened all the time.
As for wiping your save file and starting over:
In NL, never, I was suck a noob that it didn't even cross my mind xD (exemple, when choosing a map I didn't actually choose between the options I got, because I thought I was supposed to point at somewhere in the map like it was way bigger than what it actually is and I would arrive in the middle of it)
In NH, only multiple times at the very beginning, because I really wanted to try to get apples and Cherry (the villager). I was suuuper lucky and actually got both in less than ten tries! So now I'm never resetting again :>
As for (accidentally or purposefully) quitting without saving:
In NL? YES, both, a lot of times :'D I don't remember the specifics because it was so long ago, but I had built the Reset Surveillance Center to keep Resetti's job (I was so happy when I discovered you could go inside!! I was always hoping it would be open so I could continue the little story there :D)
In NH, I don't think so yet, or at least I don't remember doing it so if I did, it may have been just a tiny bit?
I played to play and enjoy the game before (wasn’t concerned about getting specific villagers or layouts). I never reset my Animal Crossing, Wild World, or City Folk games.
I restarted New Leaf three times though as it was the first time I looked at what others were doing. Some design choices warranted a reset. It also helped revitalize the game for me by resetting with the Welcome Amiibo update.
I've never reset in Animal Crossing except closing the Animal crossing gamecube game when I would forget to save and then I would be scared that resseti would come and give me a stern talking because I thought I did something bad. But I just can't get into resetting, I wouldn't be able to enjoy the game if I just kept looking at the small things that kept bugging me :c just got to make do with what you have and get creative or get suggestions from others!