Their bickering may be an annoyance to others, but it gives older people with fewer social connections and more time on their hands something to do.
Why do elderly couples argue so much? Because they can
I was sitting at a restaurant in Florida when this thought occurred to me: old people fight all the time.
All around me were senior citizens who were lunching with each other, lured by the all-you-can-eat buffet.
Elderly couples sat across the table from each other with matching white hair and salad plates. As I went around the buffet section, I could hear them talk to each other. Well, not exactly talk. More like snap.
"What are you, nuts? Don't take so much lettuce. You won't have room for the corn and you know you like corn," said one loving wife to the man shuffling ahead of her.
"I know what I like and I am not in the mood for corn today," said her husband. "Don't you tell me what to eat and not eat at a buffet bar."
What is it with old people and why are they so nasty to each other?
My friend, Anuja, who grew up in Chicago, lists several reasons why the elderly snap at each other.
"It takes a lot of energy to be nice," she says. "Think about it. You have to think about how you say something, monitor your reaction, keep your thoughts to yourself. Perhaps, as you age, you just don't have the energy to do all that.
"Plus, the myelin in your brain that allows for multiple fast decisions to come out like one smooth response, is deteriorating so you can't do it even if you want to."
As Anger Management, the 2003 film starring Adam Sandler and Jack Nicholson, hilariously portrays, it is emotionally easier to explode without thinking than to restrain yourself.
Aristotle's decree about anger sounds just right but takes a lot of energy to do.
The Greek philosopher famously said, "Anybody can become angry - that is easy, but to be angry with the right person and to the right degree and at the right time and for the right purpose, and in the right way - that is not within everybody's power and is not easy."
To hold back anger and deploy it to the right person at the right time takes a lot of discipline, that the elderly may not have.
So they snap at each other.
The world shrinks as you get older. Young people can get angry with a whole range of people at work and at home.
The elderly, on the other hand, only have each other.
They cannot yell at their grown up children; they have to be nice to the grandchildren; their siblings live far away; they don't go to offices; and many move to new cities to be near children and therefore lose their friends too. They have time and some amount of energy but mostly they don't have a variety of people to vent at.
They don't have urgent deadlines or work pressures to stimulate them and keep their minds engaged.
Maybe this is why they bicker -because it gives them something to do, something to keep their minds occupied. Or maybe this is their emotional routine.
Most couples have an emotional rhythm.
Some joke with each other; some sulk when they are mad; some scream at each other.
The elderly, it seems, follow the "bicker all the time" routine. It gets them through the day and being cooped up with each other.
The question for children is whether and when to intervene? Do you ignore, mediate or endure your parents' fights? And will you end up this way too?
My 11-year-old thinks her father and I fight a lot.
We don't - according to me.
But in her world, the occasional fight that she witnesses is grounds for the question: are you getting divorced?
I know for certain that my own parents aren't getting divorced. My dad is 83 and my mum, 77.
They have been married for far too long. They cannot stay away from each other and when they are together, they snap at each other.
This is why television was invented: to keep old people from killing each other.
Shoba Narayan is the author of Return to India: a memoir