A scenario which claims to be able to determine if someone is a good person or a bad member of society has sparked a huge debate after going viral on social media. The 'shopping trolley theory' was shared on Twitter and might make you think twice about your actions next time you've finished loading your car after the weekly food shop. It attracted more than 680,000 likes and 5,500 comments as people fiercely defended both sides of the argument. It goes like this: "The shopping cart is the ultimate litmus test for whether a person is capable of self-governing. To return the shopping cart is an easy, convenient task and one which we all recognise is the correct, appropriate thing to do. 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. No one will punish you for not returning the shopping cart, no one will fine you or kill you for not returning the shopping cart, you gain nothing for returning the shopping cart. You must return the shopping cart out of the goodness of your own heart. The shopping cart is what determines whether a person is a good or bad member of society."