I think theres a few unwritten rules around casual(With friends/etc) play.
Particularly I think if you have a zoning game good enough that your opponent cant do anything to get by it, at some point(Maybe after 2-3 rounds) you are obligated to drop it and let them actually play the game. No one likes being zoned and killed without a chance to really do anything.
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"First thing that crosses my mind: I didn't get any GameFAQs Karma yesterday." Math Murderer after getting his appendix removed.