Our most casual interactions with others, and indeed our very existence, can lead to something akin to the butterfly effect. For often very small causes can lead to cascading larger and larger effects, sometimes without end. This leads to the whole world being changed and maybe everyone's life is different due to that one very small initial act.
So, for example, smiling at a stranger can make that stranger feel ever so slightly better. She or he in turn might thereby feel more disposed to smile at others. And they in turn might smile at others. Just a small brief smile can cascade into large and larger effects and change countless lives.
Indeed, due to the butterfly effect, if one had never existed the world would be very different. Maybe better, maybe worse, more probably just different.
