Consider the "Butterfly Effect," the concept that something as seemingly insignificant as a butterfly flapping its wings in one part of the world can impact the weather in another part. The flapping wings cause an atmospheric change that then sets off a series of events that ultimately leads to something significant happening. Like the butterfly effect, one small, kind act can set off a series of positive events.
Watching this movie can help set this chain reaction of kindness in motion. You'll feel more connected to the concept of being nice, of being kind, which will help you become more aware of the acts of kindness constantly taking place around us. You'll then be motivated to contribute acts of kindness, which will add to the effect.
It's like the old children's song that said when you give away your love, you end up having more. The same is true for kindness.