I have to agree with Machiavelliest, even when piloting my eyes aren't going to be looking up at the compass. Whenever possible I try to give directions relative to the person I'm talking to (on your port, coming up from underneath you) becaues if I have time to give directions whoever I'm giving them to probably doesn't have time to spend an extra step deciphering what I mean. Cardinal directions are useful when you don't know enough to give relative directions.
Brain power's a limited resource, confusing someone can cause them to freeze up at the wrong moment.
