Have you heard of the 'shopping trolley theory'? It's been applied to management styles, tests of moral fibre etc
It is basically the theory that, given that you get nothing out of it why would you do the 'right' thing? The shopping trolley presents itself as the apex example of whether a person will do what is right without being forced to do it.
Applies to managing your waste, and picking up litter from others. When its easier to just 'do nothing' do you choose to take the time to do it right?
Servant leadership describes it well. Leading by example is another way of acknowledging this model.
Do you return your shopping trolley?