We were playing CoD zombies with my father in law the other day, and he was really struggling with the overall concept of the two joysticks for moving and looking. I realised he was consistently expecting the joystick to go the opposite way (up/down) compared to what it was actually doing. I said you have to push up to look up.

I remembered he flies Airbuses for a living, and they use a joystick, where pulling back/down is looking up. I inverted the controls and he immediately found it a lot easier to use.