Sort of in keeping with the people saying "the first one I installed", for me that was some 20 years ago with early Fedora and Ubuntu, I forget which order I tried them but it took multiple attempts over different hardware, any Linux was definitely more "difficult" back then, worse when combined with being a noob. I think some people don't know how easy they have it.

As for modern distros, it depends what you're trying to do; for example you might say something like Gentoo, but Gentoo has good documentation and is arguably "easy" for what it's specifically trying to be.

I've tried all the "main" ones over the years and the only one that's consistently defeated me is Slackware - somehow I could never work that one out.