I’m standing in a queue at a large supermarket. A woman in front of me has long since packed her shopping into carrier bags, writes Matt Gaw.

Her purse, containing a seemingly endless stream of money-off vouchers, has disappeared back inside a cavernous handbag and she is now deep in conversation with the cashier.

“I know it’s dreadful,” she says, “but he is of that age I suppose. Although you’d never guess it from looking at him.”

“I really miss seeing him”, the cashier adds, “it’s not the same without him”. The woman coos in agreement.

“Oh come on, hurry up”, I think, shuffling from foot to foot. I furrow my brow, check my watch and curse what seems to be a uniquely Suffolk phenomenon – the ritualised chat of the checkout.

Minutes later and the cashier, having finally said goodbye to the woman, is waiting for me to pick apart carrier bags for my own meagre shopping. “Morning”, she says breezily. I flash an impatient thin-lipped smile: a smile I hope says “please don’t talk to me; I just want to get home with my cat food and biscuits.”

Two days later and I’m in London for a meeting. It’s the first time I’ve been to the capital for years. The early morning sun is glinting off the new offices in Kings Cross as I walk towards Camden, skinny cappuccino in hand.

“What a cosmopolitan cat you are”, I say to myself smugly as I cross a road busy with rush hour traffic, “no trace of country mouse here.”

It doesn’t take long for me to realise I’m lost.

Sitting down on a bench, I pull out an A-Z of London from my bag. There’s no rush I think, I still have an hour till my appointment. The man sitting next to me looks equally relaxed. Suit jacket undone, he has his legs stretched out in front of him as he fiddles with his phone.

I try to catch his eye. “Lovely day”, I offer. He looks up quizzically and nods slowly, drawing his legs back towards him. Silence. He goes back to his phone.

“He’s probably not used to being talked to on his way to work”, I think, “this will probably brighten his day. Perhaps my intervention will revolutionise his commute?

“Maybe from now on his route to the office will leave behind shimmering slipstreams of conversations with strangers – numerous lives enlivened and touched by spontaneous, friendly human interaction.”

Struggling for topics and checking my own very old phone for emails, I try again. “I’ve been looking for a new phone, what’s that one like?” The man in the suit stiffens and shuffles slightly away from me.

To my horror I realise he is checking his pockets and is now putting his phone away, flicking me the occasional worried glance. “S’ok”, he manages, pushing up his glasses.

“Oh God”, I think, “Do I really look like a mugger? I must be more friendly”. But it’s too late. With a rustle of fabric he’s gone. I stand and watch his silhouette disappearing down the road. It looks like he’s travelling at some speed.

Of course, by puncturing the silence of travel – a silence that moves from packed tube trains to jostling streets – I am in breach of Big City etiquette. But putting my A-Z back in my bag, it seems to me that whether this refusal to interact is born of primitive instinct – the unknown threat posed by large numbers of strangers – or from crowd psychology, it is a dangerous habit to get into. It is a habit that means we isolate ourselves and dehumanise others.

Suddenly I feel determined. Energised even. Striding off towards the nature reserve, I greet around 90 people with a cheerful “morning!” More than half ignore me. Some just smile and say nothing. But about 15 return the greeting – an expression of what looks like relief spreading across their face.

“It is like a spell has been broken,” I think sagely.

Later that evening and I am back in Suffolk. Standing exhausted in another supermarket queue.

Ahead of me a man in his sixties is explaining to the cashier how he’s going to spend the weekend in Wales, visiting his newborn first granddaughter. They discuss names, birth weights, amounts of hair and even look at photos. Eventually, long after he has packed and paid, he leaves with a cheery wave.

I shuffle towards the till and flash a tired smile at the cashier.

“Sorry about the wait”, she beams.

“Really, it’s not a problem”, I reply, mustering all the enthusiasm I have. “And how’s your day been?”