The customer is not always right...

Bonjour tout le monde,
I read an article the other day in which the writer is having a heated conversation about a type of cheese that he wants to use in his fondue.  The cheese monger is telling him that he can't sell the writer the cheese that he wants because it is just too good to use in the fondue.  He will sell it only when the writer signs a document saying that he will not use the cheese in the fondue.
Most of us will probably think that is really crazy.  Why does the cheese guy even care about how the cheese that he is selling is used?  He's not going to be there..
But the French seem to really care about things like that.  They will tell you that they can't sell you this cheese because it's too good for the fondue, or perhaps they will not let you order two scoops of vanilla ice cream on a hot day.  Why not?  " There are other flavors, why not try one of those with your vanilla scoop?"  If you don't already know, the vanilla girl was me in 2006 at the Café of Le Grand Intercontinental Hotel at the Opéra.  His passionate argument caught me off guard, because who really tells you what kind of ice cream you can have?  The nerve!
But, I thought about it for a second, and ordered a scoop of strawberry to go with my glace à la vanille; I have to admit, it was a great combination.
Waiters seem to love lecturing me, probably because I speck French so well.  Michael and I were in Rouen with my student group.  Normally on those trips there isn't a whole lot of time for lunch and we were in a pretty nice place.  I had the best lamb tangine; Michael some sort of fish.  But time was of the essence, so when the waiter came over to ask if we wanted coffee, I said that we were under a time constraint, so could we just have the check.  He brought it, but as he put it on the table, our waiter said "Voilà, mais la prochaine fois, il faut avoir assez de temps pour un déjeuner comme il faut. (here's your check, but the next time you must have enough time for a proper lunch).

The fondue story can be found here:  https://www.thelocal.fr/20171220/fonduegate-why-the-customer-is-never-right-in-france

How about you?  Have you ever found out that the customer is not always right? What are your stories with French servers, shop assistants, or store keepers? 
Answer in the comments below - please limit them to your experience in a francophone country...

My scoops of vanilla and strawberry - very fancy!

a waiter in the traditional uniform of vest, white shirt, and white apron