Not just “oh this is for redhat and I’m on Ubuntu” but what I run into all the time is that you find a perfect guide but it turns out to be for the wrong version of Ubuntu. So most of it works until you get half way through and you get an error because they’ve switched from initd to systemd or something. Then you are stuck, do you try to roll back what you’ve done so far? Try to adapt the instructions to the new system? Then you end up chasing your tail down rabbit holes of what is backwards compatible, what isn’t, what can coexist and what can’t, etc etc etc.

If you have been using a particular distro and are familiar with the subsystems then the new version comes out and you just have to learn about the few changes in the release but for someone new it adds a whole second layer of complexity to have to learn the whole new OS in addition to trying to blindly figure out how the old system worked, what’s different in the new system and how you adapt instructions from the old one to the new one, or if you should just give up and try to find a different guide that will work.