Ok, guys my answer is going to be real quick!
LOVE YOURSELF!
HEAL YOURSELF!
TAKE CARE OF YOURSELF!
This will benefit the world the most!
I know a person who has said it in the most sublime way, in fact this is one of my favourite you-tubes ever and I especially love how he pronounces the word selfisssssss :
For more inspiring posts and answers to this same question: @ecotrain