Only when a wheel locks up or the cart wobbles do we take notice ... are well aware that the shopping cart often means the difference between a happy customer and a not-so-happy one.

Worse, if you only have one wheel lock, a smart customer could lift that wheel off the ground and ... phone to lock and unlock shopping carts. Not that we suggest you do that.

The normal carts glide along through the supermarket aisles quite easily. The ones with a wonky wheel pull off to the ... if the shopping carts exploded on impact, they would do something about ...

But the national frustration is not the work of a business psychology mastermind. The notoriously combative wheels are actually created by the repeated battering that shopping carts are often ...