I was quite satisfied with Debian Stable for a few years on at least two different laptops, and felt I had found my "forever distro", until I got a Framework laptop whose AMD graphics were quite buggy on it. In order to get rid of all the issues, I had to upgrade to Testing and install a mainline Liquorix kernel (and along the way, I briefly made a Frankendebian and fiddled with kernel parameters). While my years of experience with Debian and derivatives has prevented me from breaking anything, I do wish I didn't have to use all of this beta-quality software just to prevent games from freezing and crashing constantly, just because I bought "new" (about a year old) hardware.
I still want to keep Debian, because I've found nothing else that works quite as elegantly or stably, but I'm hoping to find ways to get the performance I need without Liquorix, and if something forces me to reinstall between now and the time Debian Trixie becomes stable, I'll probably give Fedora or KDE Neon another try.
My second distro was Debian 8, initially with LXDE (which has barely changed at all since then, so it's still nostalgic) then later switching to KDE Plasma 4. I probably hold the most nostalgia for it, even more than I do for my first distro (Linux Mint 17). For a while I was into Plasma Netbook, which I find to be an especially weird, nostalgic product of its time, and the Oxygen theme in general is probably my favorite default look for any DE.