While I was in Canada I had to re-acclimate myself to something I had forgotten was the norm up there: Paying for plastic bags when checking out at a retailer or using a reusable shopping bag.
It certainly made me think more about what I was buying and how critical each item was than if I could have just loaded up as many bags as I desired like at a U.S. Wal-Mart.
Also made me think of the wingnut couch fainting that would inevitably ensue if similar policies were enacted in this country.
Personally, I like the idea of a reusable bag for cutting down on waste.