When playing a video game where, say, the right joystick controls the camera, I set it...
Direct X&Y. push left to look left, push down to look down
Inverted X&Y. push left to look right, push down to look up (camera behind your head style)
Direct X, Inverted Y. push left to look left, pull back (push down) to look up (airplane style)
Inverted X, Direct Y. push left to look right, push down to look down (Polish submarine style)
Right joystick? I only have one joystick, and it has a big orange-y-red button on it.