Random acts of kindness increase happiness

I've been reading through a few books on positive psychology during my vacation, and I came across an awesome bit of research that found that consciously performing acts of kindness increases happiness (as long as those acts aren't overwhelming to perform).

Experiments have actually demonstrated again and again that kindness toward others actually causes us to be happier, improves our health, and lengthens our lives.

It doesn't even have to be a big thing; it can be as simple as holding open the door for someone, helping someone carry a heavy bag, etc.

Pretty obvious in hindsight, and yet, awesome nonetheless.