I knew what was coming even though I willed it to be otherwise; a perfectly decent conversation about food was about to be ruined by a friend who loves cooking and therefore thought it would be a great idea to start a restaurant.
"Have you done any professional cooking?" I asked.
"Well, no, but I cook for lots and lots of people," she replied.
"Yes, but that's not quite the same thing," I said without conviction because, if you are in the restaurant business, you become a magnet for people who plan to improve on the formula of making a small fortune out of the restaurant business, providing - and this is vital - that they start with a large one.
A widely quoted figure is that 90 per cent of restaurant start-ups end in failure. This may be a little harsh but it is safe to say the overwhelming majority fail.
What is it about restaurants that encourage otherwise perfectly sensible people to throw their money into a large cooking pot, boil it to extinction and then declare that the pot itself is to blame?
Honestly, it's a mystery.
One person told me he had a brilliant idea for a vegetarian restaurant that would not sell alcohol because this would be a distraction.
When I meekly pointed out that in most restaurants alcohol sales tended to subsidise the food, he looked at me as if I had dragged a dead cat into the room.
Then there is what may be called the "fusion affliction" - the symptoms of which are seen when two perfectly good, but generally incompatible cuisines, are fused to produce something that is bizarre and much less than the sum of their parts.
One bright idea for an Italian-Chinese fusion restaurant was predicated on the truly astonishing insight that as noodles feature in both food cultures they could be cobbled into a single cuisine.
I seem to recall that this brave project did not get off the ground, but I saw that someone else was struck by this same insight and opened a restaurant that predictably closed shortly afterwards.
Meanwhile, I find myself playing the role of the unfeeling, unsympathetic party pooper who expresses scepticism towards new restaurant plans.
If someone came along and asked how much it cost to set up a kitchen, the average food costs and maybe even the margins that can be expected, I would listen more carefully to their plans.
But this rarely happens because new entrants to the industry tend to be bursting with ideas for the type of food to be served, the décor and just about everything except for how to make this into a business.
The reality is that the food business is hardly glamorous, particularly at the kitchen end of things and it demands very hard graft and an enormous degree of patience in dealing with chefs.
As actor and restaurateur Michael Caine remarked when told that actors tended to be temperamental, he nodded sagely and asked: "Have you met any chefs?"
Yet restaurants seem to be a magnet for people who in other areas of life are quite sensible. They declare a fervent "passion" for food and tell wondrous tales of their skills in their own kitchens, which they believe can somehow be translated into the skills required to run a restaurant. The stark truth is that most businesses do not become successful solely because of the passion of their owners but as a result of the application of sound business principles.
Ray Kroc, the man who made McDonald's into a global behemoth, always claimed that he never invented the hamburger but mastered the technique of mass-producing it.
As I write these words I can figuratively hear the sighs and tut-tuts of foodies, who shun the Big Mac. Let them snigger, but they cannot deny the genius of a man who discovered a formula to feed people from Arkansas to Accra with products they really like and will line up to buy.
Meanwhile, the person who was thinking of opening an alcohol-free vegetarian restaurant seemed insistent that I show enthusiasm for his project and grew increasingly agitated when I pointed out some of the problems. "Thanks for ruining my dream," he said bitterly the last time we met.
Was I really hoping to be thanked for saving him a small fortune?
Stephen Vines runs companies in the food sector and moonlights as a journalist and broadcaster