His recent piece in the New York Times described his retreat on Puget Sound in such lyrical terms – blue herons, swallows, spectacular sunsets etc – as to evoke the Buddhist hindrance ("sin" is out) of envy.

But more than that – as a number of bloggers immediately pointed out – it led to questioning the point of idyllic retreats in general. If William Blake could find heaven in a grain of sand, then shouldn't we look for it in a thrown-away tube ticket and a MacDonald hamburger? Is it really necessary to retreat to settings of unimaginable tranquillity in order to attain tranquillity? And even if you got it, how long would it last?

There is the story of the monk who went off to his cave and meditated for seven years and concentrated on purifying the mind. When he emerged into the light of common day at the end of that time, he was thoughtlessly shoved aside by a small child. And instantly lost his temper. Farewell, merit.

Those small irritations of life do not feature on retreats. And nor do emails, mobiles, crowded tubes, traffic jams, getting meters read, tackling the taxman, dealing with sick child and cross spouse. Of course, the belief that you can actually "get away from it all" turns out to be illusory, and you inevitably discover you have brought "it all" with you in your luggage. But the speed of ones reaction slows down, not to mention the affect of having one's bodily needs looked after.

The temptation is to see a retreat as a break: a sort of spiritual time-off and a counter to the stress of the everyday. And indeed, ones busyness does generally calm down and ones defences do drop. If only, you think, life were always so tension-free, how easy it would be to be nice/wise/compassionate. It is remarkable how quickly a tribal feeling can develop and the retreat end come to be marked by a feverish exchange of addresses and emails as you leave the group that you feel saw the real you. Return home and you encounter ordinary people with their own ambitions, projections, egos and demands.

But if retreat-mode can't be carried there, what is it worth? That's the logic behind the street retreats that were pioneered by Bernie Glassman. A charismatic American Zen teacher with enormous chutzpah and resolve, he set them going in New York and created a model that has since been followed in several European cities. Glassman led his students out onto the streets of the Bronx where they slept rough for a number of nights, ate in soup kitchens and begged. The very first one in London several years ago attracted sizeable press mockery because it was assumed it was devised to help people understand homelessness. In three days? scoffed the press, and all the homeless organisations expressed outrage. That would of course have been foolish, not to say blindingly patronising. Its true point however was to strip away people's support mechanisms – even watches had to be discarded at the start – and to expose reliance on habit, conditioning, status and security. How well that works is a matter for personal experience, but it is certainly a counter to blue herons and fine sunsets.

When the Korean master Seung Sahn wanted to set up a centre in New York, he instructed students to look for a place on the busiest highway they could find. Another time, in the mid West, he dragged them into a casino in the middle of the night where Las Vegas' hard-core gamblers were still obsessively at it. "But isn't this against all the tenets of Zen?" asked the shocked students as he urged them to gamble. "if you do not understand their kind of hell,' he replied, "how can you save them?"