We don't have much choice. The restaurateur has by this time already started "softening up" the occupants of the selected table, and they are sitting there, also smiling, within earshot. To decline would be regarded as an act of snobbery. So, instead, we dine in the company of people who resent our presence and probably hate us.
The tables are tiny, our elbows continually knock against each other. Yet we have to act as if the strangers weren't there, and they do likewise. Two separate, stilted conversations are conducted as people try to be separately intimate over shared candles. The whole arrangement is most uncomfortable for all concerned, and eating the meal becomes a chore to be got over with as soon as possible.
This generally happens in establishments that have suddenly become very popular and trendy, and where the owner has not yet learnt to say, "Sorry, we're full up." People queue around the walls or between tables and, like vultures, stare at those who have obviously finished their meal, but who are taking their time to pay the bill.
All this happens in very cramped conditions, with waiters forcing their way through every few seconds. These places usually have a floor space of about 20sqft, so that most of the tables are practically touching each other anyway. And for some reason the tables have legs which are all of different lengths so that they wobble about, and one of the waiters is considered to be a bit of an expert at levelling them up, so that you have to thank him profusely as though he has done you some special favour.
And leave a tip.
After a while, regular customers start to familiarly address the owner by his first name - "Hi, Otto. How are you tonight?" - as if they are old friends. And he smiles and pretends to remember all their names. This makes them feel like valued clients - which is why they pretend not to mind sharing tables with strangers.