I recently learned about the Shopping Cart Principle of Goodness. This seems like a good measure. And to answer your question, yes, I always put my cart back.

"The shopping cart is the ultimate litmus test for whether a person is capable of self-governing, the post states. To return the shopping cart is an easy, convenient task and one which we all recognize as the correct, appropriate thing to do. To return the shopping cart is objectively right. There are no situations other than dire emergencies in which a person is not able to return their cart. Simultaneously, it is not illegal to abandon your shopping cart. Therefore the shopping cart presents itself as the apex example of whether a person will do what is right without being forced to do it."