Shopping Carts in Parking Lots – A Question of Etiquette

I think we can all agree that shopping carts have wheels and in most cases are fairly easy to move around.  Their wheeled design lends itself to easy conveyance of goods at any number of commercial establishments.  Typically, these places of business provide locations in their parking lots where customers can return these carts when they have finished loading their purchases into their vehicle.  My question is this – Why is it that some people simply REFUSE to put their cart back in the fucking corral?!  Instead they just leave them sitting there in the middle of the parking lot, usually blocking a parking space that would otherwise be available.  Not only are these abandoned carts an inconvenience for people trying to park, but they present a hazard to the other cars in the parking lot.  We’ve already established the design paradigm of shopping carts having wheels, so add some wind and you’ve got plastic and steel torpedoes whizzing around the lot.  Whizzing around, that is until it’s stopped by the unfortunate placement of another persons vehicle.
Today when I came out of the grocery store I saw no fewer than eight shopping carts left strewn about the parking lot between the front of the store and my truck.  The kicker is that most of them were within four parking spaces of the corral.  Have people really become so self absorbed that they either don’t understand or don’t care where their cart should go?  Are people so lazy that walking the width of a few parking spaces in too much of an inconvenience?
Enough ranting, I have to go put my groceries away and touch up the shopping cart ding in the side of my truck.