Handles are an important part of the bag

From a larger article in Sunday's Star:

When Irish officials resolved to charge a fee for plastic grocery bags, they didn't use detailed economic calculations to determine the optimal number. They went for simple shock value – what amount would make shoppers think twice before taking a disposable plastic bag to carry home, say, a loaf of bread already wrapped in plastic?

The point - the need for a bag - is not to protect the bread from dirt and elements. It isn't that I specifically want to wrap the bread in another layer of plastic. The reason I get the bread in a bag, even if that's the only thing I'm buying, is that the bag has handles.

If I were to carry a loaf of bread home without a bag, that would take up either a hand (if I held it by the end of its plastic bag) or an arm (if I cradled it). I'd have to be at least a little careful with it so as not to drop it or squish it. But if it's in a plastic bag, I hold the bag by its handles or hang it from my wrist - whichever's easier and usually switching between the two as I go about my business - so my hand and arm are almost entirely free and I don't have to make the effort to protect the bread.

"Big deal!" you're thinking, "How much trouble could that be? What harm could possibly befall a loaf of bread on the way home from the store?" Not much if all I did was buy the bread and take it home. But I do a number of errands on the way home from the office. Today when I arrived at the apartment door, I was carrying six full shopping bags from three different stores, two newspapers, two library books, a letter, a parcel, and my keys. The shopping bags were all hanging on my wrists by the handles - I couldn't have carried it off any other way. And even with the convenience of handles, I was still soaking wet because I didn't have a free-enough arm to hold up an umbrella.

This is why even if an individual item doesn't need a bag, the shopper still might. This is why those LCBO paper bags with no handles are downright insulting. And this is why people need to think of the logistics and choreography of the entire trip chain when trying to determine our bag needs.