Weird shit like, Linux refusing to let me copy files on an external hard drive because "I'm not the owner" of those files. What the hell? I've owned these files for 20 fucking years. Linux telling me I don't have permission to access my own files. GTFO.
Another big issue is lack of software. The alternatives just don't measure up. Graphics and audio editors are garbage. Gimp ain't Photoshop. A similar issue used to be games, but Valve's been fixing that very rapidly.
And then there's the analysis paralysis of too much choice. What distro do I go for? There are over 500 distros actively maintained. You'd need to study this for years to choose well. I ain't got years to switch, I need to work now.