Imagine a door. Imagine further that you have a key that opens that door. You can turn the key either clockwise or anti-clockwise and only one of these turns will actually open the door. One of these two turns is intuitive and the other one is counter-intuitive: if the door handle is on the left side, then the clockwise turn is intuitive and the anti-clockwise turn is counter-intuitive; if the handle on the right side, then vise versa. Regardless of door handle locations, all doors at Caltech that I have opened so far are opened by the counter-intuitive turn. On contrary, all doors at USC that I have opened so far are opened by the intuitive one.