Switching keyboards and commands from a PC Linux computer is driving me crazy - command + z, x, c, v are all so cramped and awkward to move to from the home keys compared to left control. I can't get used to command + R as refresh versus F5.
I also hate the Apple worship that I feel like is all over the internet when I look something up - if some decision made by Apple makes no sense they'll defend it to the death. IE hiding a "lock computer" function not in System Preferences->Security or Users or even screensaver, but you have to open Keychain->Preferences, enable "show keychain menu on menu bar". From there, you have to click the keychain menu and select lock the computer. How does this make sense?!

Wow - Paul's old dell. That thing was a monster machine. I wanted it at one point. :P
Occasionally crapple "features" get the better of me and I want to throw rocks at the screen but over time I have learnt to painfully fix everything to the linux defaults and never ever use the GUI. With a terminal, I don't even notice the difference and hardware is much more reliable.
And crapple sheep. Let's not even get started. They have to be from the middle ages before Renaissance came in.
I think no OS is perfect. NONE. The lesson for me is that you engineer your computing environment and tweak it till you reach a kind of equilibrium that doesn't come in the way of your main work. I have Paul to thank for this enlightenment. :)