Shopping Cart Theory

An everyday test over morality and responsibilty over the simple task of returning a shopping cart after unloading groceries. You aren't forced by the law to return it, you won't get any punishment for not returning it, you won't get rewarded for doing it, it doesn't take a lot of time or effort to return it, but it is the right thing to do and it organises the parking lot and makes it easier for the next people to use the shopping cart. Most people should be able to return it unless they are in a hurry. Ultimately, it's a test to see if people can do the right thing without being forced or rewarded.

"You're just gonna leave that cart there?"
"Yeah."
"You failed the shopping cart theory."
"What the hell are you talking about?"