To dine in a restaurant is to appear in public. Most of us, these friends included, clearly understand the forms involved in going to a restaurant. You're greeted by the host, who leads you to your table; a waiter appears, either with menus or with a greeting and query as to whether you want a drink before dinner; a busser appears to handle the water, bread and butter, and such things.
You don't expect to see the host again, though he may appear at some point to verify things are going well. Your transactions with the restaurant will all be conducted through the waiter. The busser will continue to serve you silently, taking dishes away, filling the water glasses, perhaps replenishing the bread.
Diners and service staff rely on these forms as a social convention facilitating the dining experience; diners and service staff interfering with the convention risk interrupting the smooth flow of the meal. The diner needs to be aware of the extraordinarily demanding nature of the waiter's job, the complexity of the host's (he functions as manager and spokesman for the restaurant as well as greeter and conductor-to-table), the numbing repetitiveness of the busser's endless pursuit of silent perfection.
The service staff, on the other hand, needs to be aware of the desires, even the demands, of the customers, not only for their table but also for its effect on the floor as a whole, the many tables, each aware to one degree or another of its neighbors. For this reason the customer's demands must be given highest attention — even anticipated when possible. When a diner makes the first demand, requesting a certain table, say, or volunteering without question a preference for ice water without ice, he's all but hoisting a flag: difficult patron here.
Over and over I've noticed three kinds of response to this. The optimal one of course is immediate understanding. This involves deference on the part of the service staff, but I suppose that's what "service" ultimately means; a professional host or waiter or busser realizes that there is nothing demeaning or servile in his metier — on the contrary: if unusual service is demanded, fault, if any exist, lies with the customer.
The second is a deference to the patron that's accompanied by some expression of criticism on the part of the server. This is unfortunate. The customer notices it more often than the server perhaps realizes, and an unsatisfactory relationship develops which, since it's never really expressed, can't really be resolved.
The third is the worst of all: everything goes to hell. Each side of the transaction takes deliberate steps to make the other side's participation more difficult, raising the ante. Voices may be even be raised; nearby diners are affected; dissatisfied patrons go away sulking and perhaps publish their discontent. (This is exacerbated by the prevalence of blogs and of "reviews" on restaurant-finding computer applications.)
I've listed two demands triggering this sort of situation: table request; ice water without ice. There are many others:
and I'm sure others could be added.
"allergies" (many or most of which are in fact simply food dislikes) split or shared plates courses desired out of sequence corrections of dishes implicating the kitchen's competence (salt, etc.) inappropriate expectations (espresso machine in a Chinese restaurant)