Again, though, these are stock phrases, a necessary evil of dining. It's when a server ventures into personal opinion that I truly bristle. Specifically, I bristle when I or a dining companion orders a specific dish and the server replies, "Excellent choice" or something along those lines.
I know the server means well. And part of me does appreciate the honest enthusiasm, as opposed to chef- or manager-mandated pushing of a certain dish. But it's still an absolute no-no.
The reason why should be obvious. If not, here, drawn from personal experience, is a one-act play describing what happens:
My Wife: I'll have the shrimp.The human palate is a wonderful thing -- but also wonderfully strange. Psychology plays a part. In this case, even the slightest doubt about the quality of a dish could spoil an otherwise decent meal.
Server: The shrimp. OK. And for you, sir?
Me: The duck breast, please.
Server: The duck breast. Excellent choice!
Server walks away.
My Wife: (Nervously) So the shrimp isn't an excellent choice?
Declaring someone's choice "excellent" also sows doubts about the restaurant as a whole. If another dish isn't an excellent choice, why is it on the menu in the first place? Is the chef truly dedicated to his or her craft or just some hack slinging hash for a paycheck to the unwashed masses?
Conversely, declaring a dish an "excellent choice" heightens the diner's expectations. If the dish delivers, no problem. But if it's merely good instead of great, the disappointment can be disproprtional, again spoiling an otherwise decent meal.
Variations of this practice -- "The duck breast is my favorite!" -- are less damaging, but still annoying. The ideal server should be like the ideal journalist: You should understand and be able to describe and explain the menu, noting, say, that this dish is a riff on a classic, that aspargus is in season, and so on. But your subjective opinion has no place in the report.
Finally, a caveat for diners: If you ask the server for his or her opinion -- "Do you recommend the oysters or the scallops?" -- and disagree with the response, you have only yourself to blame.