No matter how we younger gentlemen tried to explain the glorious simplicity of the thing, he just couldn't kick the button-up habit.
It wasn't that his fingers were innately more nimble than ours - certainly not - nor the religious or philosophical objections of a Luddite to modern technology. He simply knew his way around a button-up fly and felt too old for the challenge of something new.
It wasn't a visit to one of Savile Row's finest that brought back the memory, nor the sort of accident that might bring a tear to the eye of a drinker too eager to rejoin his mates at the bar after a comfort break, though I was in a pub when the idea struck me. I had just been mocking the role of Twitter in the lives of the younger generation.
I thought I was on safe ground. It is an argument that I have rehearsed a number of times: Young people today have too much time on their hands and are too impressed by something new. They aim to follow or be followed by more Twitterers and to send out and receive more tweets than their mates. As a result, the Twitter network is overflowing with inane messages about nothing. It is new at the moment and has cult status, but mathematically it doesn't stack up. The vast majority of tweets will not be seen by anyone, so what is the point?
But my mate put me right. Twitter does not exist to allow one person to tell a million that he has just had a cup of coffee. It is a search engine. It is there to answer questions. You tell the Twitter world that you are looking for a good place to buy a plant for your aunt as you travel up the A38 to Burton and someone gives a recommendation. I cannot say I understand how it works and I cannot say I will ever get to grips with it, but plenty of people out there do and will, and I am grudgingly convinced that it is a powerful marketing tool.
The world was kind to my grandfather. There must have been times when my grandmother wished that he would embrace the latest technology - it was not easy to find buttons toward the end, but she managed, somehow, for his sake. It will be less kind to my generation. Today's technology is even faster, even more impressive, than the zipper fly and we ignore it at our peril.
Tim Edwards is chairman of Boningale Nurseries.