"To rejoice in another's prosperity is to give content to your lot; to mitigate another's grief is to alleviate or dispel your own."-- Tryon Edwards

Tryon really gets that we are all one.  The whole "no man is an island" thing is illuminated here.
It's culturally easy to be jealous of someone else's good fortune or too greedy to "mitigate another's grief" because our culture of the rugged individual keeps us believing that we're all on our own.  It's a very dog-eat-dog (my apologise to dogs) way to look at life, and keeps us suspicious of one another.
Random acts of kindness are the remedy.  They feel good to us and to the recipient, and when we feel good, we do good and when the recipient feels good, they do good, etc. etc.
As you can see, there's a chain reaction that occurs here that ultimately benefits everyone.
Start the ball rolling.