I loved Gentoo, and in fact, I used it for longer than any of the other distros. But I didn't switch to OS X because I couldn't figure it out. Once I had everything configured to my liking, which, of course, takes quite a while on Gentoo, I didn't have a problem with the OS or how it performed on my system.
The problem was that I couldn't go to a store and buy anything. Hardware would only work if it's an extremely common type of hardware with standard drivers.
Buy a new wireless headset? The software to make it work (beyond just playing audio) is Win/Mac only.
I bought an iPhone before Android even existed. Software is Win/Mac only.
I don't like GIMP. I much prefer PhotoShop. Win/Mac only.
I like watching Netflix on my laptop. Win/Mac only.
I bought a Jawbone bluetooth for my phone. I can only configure it and change settings with Win/Mac software.
Something new, like Spotify comes out? Win/Mac only (although they have an unsupported Linux client nowadays)
It's random things like that that turned me off from Linux over time.
(And before anyone says it, using Windows in a VM would defeat the purpose, IMHO. And WINE, while nice, isn't foolproof either).