Personally I haven’t. While Linux is imperfect, choosing the right distro makes the rest of the experience straightforward. And with it’s whole complexity, I find Linux more user friendly than Windows. Even driver issues, broken shadow file ownership and KDE specifics only made me more confident about my choice to use Linux after I solved everything.
It’s difficult to be disappointed with something that is free.
Actually, one shouldn’t be disappointed with things. Only people can disappoint you.
I was disappointed in the Debian crew when they standardized on systemd when it clearly wasn’t ready yet.
And I was disappointed in the people running some distros that made Wayland the standard when it clearly wasn’t ready yet (a few apps I rely on don’t support it or run poorly on Wayland even now).
Other than that, free software, free choice, and a lot of learning possibilities. You just have to adapt your expectations. Change hardware, change software, change distros, and learn.