I have always wondered what is one to do if you try to open with a specific opening, and your opponent just opens with a random order of moves and doesnt follow any real theory or correct order of development. Do you just continue with your opening theory, or do you try and assimilate to your opponent's opening and follow basic rules of the opening?
I would concentrate on playing chess.
Really, playing the Ruy Lopez when your opponent chooses to play the Scandinavian defense?
Seriously, as somebody once said "Learning openings learns you openings, learning endgames learns you chess".
Also, be prepared that when you play 1.e4, your opponent wont always play 1...e5 In fact, he'll more often than not play 1...c5!
Finally, when there's more than 1 possible continuation to your opening choice (ex: Queen's Gambit Accepted/Declined), I say you learn a simple line against all mainline variations (that is, not a 10 move long variation).
~~Rolex575~~