Carry the Burden
We’re living in a civilized society, and that means we have a responsibility to the other people living among us. Part of that responsibility is putting the shopping cart in its proper location after we’re done with our shopping. If we’re not going to do it, who’s going to do it for us?
Unfortunately, most people just don’t care what happens to their cart after they’re done shopping, and they don’t care if the parking lot becomes a mess of shopping carts. As this meme points out, the people who actually put the cart back in its place are carrying the burden of the world on their shoulders.