For example, just because your experience in restaurants in the U.S. is that they MUST, by law, serve you, well, it's just not reality in Mexico. And the lovely saying that "the customer is always right" is certainly not true here. And maybe that's a good thing. Why should anyone with any pride or feeling of self-worth allow a customer to treat them with rudeness or disrepect? And the gringo attitude that the most important this is making money just don't wash for many people in Mexican. At least that's my observation.
Many businesses in Mexico are very small, family-run, businesses, where the family eats, sleeps, bathes, washes their clothes, does their homework, and raises the children. And entertains their friends and socializes. Entering a small family business is very much like entering someone's home.
They have no obligation to serve you. It might be a good idea to serve you, if they want to make money. But that's not necessarily a cultural priority here. Family and personal pride seem to be valued much more than making money, at least in the older generations in Mexico.
and partly real.