Sleep and Audio are definitely my most annoying, and prominent, issues that I run into. Devices like USB audio interfaces I find tone temperamental. Oftentimes they will not be recognised on startup and I have to unplug them and replug them back in. I also gave up on hibernate, my PCs are now either on or off…
I love gaming on my Linux machine, and for the most part it is a pleasant experience. By far the worst outcome is when an update breaks a game that was working perfectly fine. This seems to happen regularly, especially with online games.