100 little things to make this world a better place

Inspired by Alice, my flatmate when I was in graduate school, I've decided to share with my readers little things that we can easily do (but don't usually do) to make this world a better place.

I am targeting to list 100 little things in 2012 - in different categories. You may know all these little things but somehow we forget or we are not motivated to carry them out. I hope you'd join me to take the first step and be persistent, and when we look back at the end of 2012, we'd agree that we've done some good deeds for this world.