In a recent review for The New York Times, Pete Wells courted controversy by downgrading what his predecessor had rated a top four-star restaurant, the iconic Daniel, giving it only three stars. He had only minor problems with the food and no quibbles at all with the attentive service he received, which was no wonder, considering the staff recognised him and knew he was the restaurant reviewer of a highly influential newspaper.

However, an anonymous colleague who also dined there on the night of one of Wells' visits - and who sat nearby and ordered from the same six-course, US$195 menu - received the same quality of food but a signifi-cantly different level of service. Sure, it was polite and professional, but the inconnu's wine glass stayed empty for some time; he didn't receive a fingerbowl after a dish that he had used his hands to eat; he wasn't offered a cheese course; and the staff didn't ask whether they could find him a taxi as he was leaving the restaurant.

I've been recognised in restaurants on several occasions, both when reviewing an establishment and when merely enjoying a meal with friends. I can usually tell when I've been spotted and always carefully observe the service given to diners around me, to see if the staff are just as attentive to them. Whether I receive an extra amuse bouche, as Wells did, isn't a big problem to my mind, because it's always natural for chefs to be more heedful to certain guests, and not just food critics. But if the waiters are polite to me and snarl impatiently at guests at the next table, that would be a major problem - and one, I have to say, that I have yet to encounter.

When eating at a top restaurant, most of us have certain expectations, although what they should be is up for debate - after all, there's a fine line between attentive service and service that is obsequious, and two guests dining together might have opposing views about which is which. Moreover, while some wine lovers get irritated if their glasses aren't topped up by the waiter, others like to see how the wine develops in their glass, and pouring fresh wine into a glass that still has a few sips left in it means they can't do that.

Waiting tables, especially in expensive restaurants, is fraught with difficulties - it's not just about taking an order, serving the right dish to the right person and refilling water and wine glasses. Staff have to deal with the people on both sides of the swinging doors: the harried chefs and cooks in the kitchen, and the paying guests, many of whom have the sense of entitlement that comes with wealth. There are also cultural differences that need to be taken into consideration: in some countries, it's expected that waiting staff are aloof and "correct", while people from other parts of the world will see this type of service as cold and impersonal.

As Wells writes, "A restaurant can't be blamed for trying to impress a critic. It can be faulted, though, for turning its best face away from the unknowns, the first-timers, the birthday splurgers, the tourists. They are precisely the people who would remem-ber a little coddling at a place like Daniel for years."

And besides, you never know who "the unknowns" might know.