In the early part of the 20th century, most people bought their food from small emporiums where they would have to ask a clerk for items stored behind a counter. That all changed right around the beginning of the Great Depression.

At that time, Michael Cullen, an employee at a Kroger store in Illinois, sent a letter to the company’s CEO explaining his idea for a large store full of items stocked in aisles that people could select themselves. The stores would have large parking lots, and certain items would be deeply discounted to draw customers.

Kroger’s CEO didn’t respond, so Cullen leased a vacant warehouse in Queens, N.Y., where he established King Kullen, ostensibly the world’s first supermarket. Needless to say, the idea caught on, and we now have more than 36,000 supermarkets nationwide.

I have been to many of them. I spend several hours a week in one grocery store or another, and while some people might hate grocery shopping, I have tried to adopt a zen approach in which I view grocery stores as food temples where I am alone in a crowd, just me and my list, waltzing along to the wonderful music wafting from the public address system.

But many elements of the shopping experience can break this trance-like mood. And most involve shopping carts.

Not much happens in a grocery store by accident. We all know that, to get to the meat or milk section, we have to navigate aisles packed with items to entice us – cereal, chips, drinks, candy. We know that offering us two items at a special price prompts us to buy two even though we could get one at the same discount.

And we know that aisles are intentionally narrow to slow us down and tempt us to make more dumb impulse purchases. But this has to be a careful balancing act on the part of store designers because it is here, in these narrow aisles, where shopping carts jam up. It is here that we get the urge to tear up our shopping lists and run screaming from the store.

Zen? No, bad karma.

Some people are oblivious to the fact that they are blocking an aisle with their carts. They will stand in the middle of the aisle, taking up as much room as possible while they read the list of ingredients on the can of soup they are buying.

“How many carbs in this soup?” they wonder as people begin to bunch up around them. I usually just turn around and go to another aisle.

Women (and, sexist as it might sound, it’s women more than men) seem to regard their carts as an extension of themselves. They cling to their carts, using them as blocking devices to protect the space around them as they shop.

I sometimes leave my cart at the end of the aisle while I grab something from the shelves. This would be unthinkable for some: Lazy shoppers might take items from my cart if I don’t hold onto it!

Many shoppers, I have noticed, keep at least one hand on their cart at all times.

The other day, I went to the refrigerated food section to buy some orange juice. A woman was standing in front of the open cooler door with her cart at her hip, blocking the entire juice compartment. I waited, and then waited some more, thinking that any second she would reach a decision – Tropicana or Sunkist? – but she just stood there, staring at the orange juice while the windows of the cooler fogged up.

Finally, I knelt down, reached between the cart and her legs and grabbed a carton of OJ (Tropicana).

“Oh, sorry,” she said, finally noticing that there were other customers in the store. But she didn’t budge, and soon was back to surveying the orange juice.

Children are another issue. I realize that people have to take their children to the grocery store sometimes. I did when my kids were little.

But an aisle full of children is a frightening and dangerous place to be. Most children never watch where they’re going, so they constantly run into carts or knock stuff from the shelves. Often they do this at full speed. At other times, however, they simply stand in place, apparently catatonic, blocking the way until a parent wakes them up and makes them move.

And sometimes there is screaming.

Then again, when the zen is working, moving around the grocery store can be a breeze. Pathways miraculously open up for your cart. You are able to deftly cut around the elderly woman who is barely moving. You are able to swerve in front of the clueless shopper who is paying no attention to what he is doing. You avoid the large family in the bread aisle by expertly shifting tactics and heading for the dog treats aisle instead.

Experience counts for something in grocery shopping. Only the timid and the untested get stuck in an aisle for long.

So, see you at the grocery store. I’ll be the guy with the sly smile and a cart full of impulse purchases.

James Werrell, Herald opinion page editor, can be contacted at 329-4081 or, by email, at jwerrell@heraldonline.com.