Have you read the shopping cart theory?
I will post it in the comments but in summary this is a fascinating observation about human nature.
The idea is that returning your shopping cart is one of the easiest things you can do yet there is no reward for doing so. Nor is there a punishment for not returning your cart.
So what do you think? Is returning the cart important or not?
Have you noticed a difference in the “rate of return” depending on where you are?