Its hard to use metaphors and analogies here because you have to consider all of the implications and breaking points because you know someone is going to draw them out ab absurdum.
I think that most people understand that your role in the story was "generic customer" and that the story wasn't supposed to be about your actions at all. You were supposed to be the black box and the restaurant the introspected actor.
We troll the ones we love the most. It's a subtle form of compliment.
You're right, you don't owe her anything. Or yourself. Just stay home with clenched fists and stay angry about it. Be sure to have some aspirin handy in case you have a heart attack.
Call me crazy, but just for fun, you could try a mental experiment: imagine for a moment that she is in fact a deeply wise and loving person, and she was at that time doing just the right thing to teach you perfect patience. Just saying, neither you nor me can prove it true or false. Just saying, you know, it's a way to look at it.
By the way, that's a gorgeous picture on your blog. Makes me want to go travel.
Your post bothers me. You're setting yourself up as the 'better man' and making it so you can mockingly dismiss anyone that disagrees with you.
Studies have shown that the most difficult customers are often the least profitable. It's pretty widely known.
Seth Godin: http://sethgodin.typepad.com/seths_blog/2010/02/more-more-mo...
Entrepreneur magazine: http://www.entrepreneur.com/article/173108
How often have you seen the owner of a well-managed business say "I'm done with this guy" after only one incident? I admire this woman. She not only provides a quality product with good customer service, she knows when to cut her losses.
Don't advertise something you don't plan on honoring, and you don't have 'difficult customers.'
You can say it's ironic that he is "applying a different standard" to the two actors in the story, but that's just point scoring, and reality is subtler. Society holds the two parties to this relationship to different standards. By going to a local restaurant 15 times and paying their higher prices, he has more than demonstrated good faith in such a relationship. He has stayed truer to this restaurant than 95% of customers to local restaurants. The owner, on the other hand, has the obligation of providing excellent customer service, which is what society expects of a local restaurant who charges high prices for their food (the breakdown of this expectation is parodied in the Soup Nazi character of Seinfeld). Given how awesome repeat customers are for local restaurant businesses, it should have been intuitively obvious to the owner that they should have let it slide, or at the most said something like, "well technically this one doesn't count towards the promotion but I'll give it to you anyway this time." The fact that this wasn't obvious to the owner when it's SO BLATANT to us indicates that it's this person's entire mode of thinking. This is supported by the bad Yelp reviews for service the author noted in this comment section.