Hardware compatibility. I have one machine that won't boot any Linux installer at all. Another with constant gpu driver problems. Another where Bluetooth doesn't work at all. Another where wifi firmware crashes all the time. It never ends.

Hell, even if you do go into the command prompt it's pretty easy if you're on something Debian based, apt is really easy to get a hang of.

"Why does my .docx document look all mess up on my computer?"