This is easily number one. I enjoy my computing experience when using Ubuntu. Whether it’s just using the computer for usual human things, noodling with new software from source, or getting new hardware working. It’s fun. I don’t find Windows or MacOS fun, at all. They work, but they’re not fun.
My Ubuntu systems are reliable. They don’t ever randomly break (much).
I’ve been using Ubuntu now for eighteen years. I know (roughly) how it works. I am familiar with the release cadence and set my expectations accordingly.
As you can see from my heterogenous list of devices, the majority run Ubuntu. So being able to try something on my laptop, and then be able to run the exact same command on my server, is pretty handy. Even though they all run different releases of Ubuntu, most of my systems are able to run the same software.
Referenced podcast on Linux Downtime
I feel pretty much exactly like OP. It (Mostly) Just Works, and has for almost 20 years.
Also like OP, I think the snap transition has been thoroughly screwed up. It is the only reason that makes me - on occasion - long for Debian. I wish Canonical would just cure itself of NIH syndrome and drop it entirely. (Not necessarily in favor of flatpak or appimages, either. I like debs.)