Goodness: people deserve to be treated well. Regardless of how they treat you or others.
Justice: people deserve to be treated like they treat others.
Why is this model useful? It helps your awareness of how you treat others and yourself. This allows you to reflect on whether this is how you want to treat people.
How do you treat others? Strangers, friends, family…
How do you treat yourself?
Do you treat yourself differently from others? Why? Do you believe yourself to be more/less deserving than others?
(src: 7 Habits of Highly Effective People)