The stranger is an element of the group itself, not unlike the poor and sundry 'inner enemies'—an element whose membership within the group involves both being outside it and confronting it.
The only thing that can make you a hero is your heart.
A good abstraction is one that captures the essential aspects of a concept while ignoring the irrelevant details.
Happiness is not the belief that we don't need to change; it is the realization that we can.