I don't think this example really hits the mark. It fits better if the kebab man says " You are my very special friend! I give you a special discount because you are my very special friend!". And he does so a couple a times. Then the next time you walk in the joint you see that you're not his very special friend anymore becasue everybody is getting the discount. This kind of behaviour results in a strange psychological effect that makes people that actually have gotten a discount think they have been wronged. And on a psychological level that may even be true. But I'm no shrink so don't mind me