Y'all talking about kindness is this, kindness isn't that, got a short story for you...
George Price, basically developed what is still the best accepted evolutionary, mathematical and biological interpretation of altruism.
Basic idea is, that you're more likely to be altruistic towards those more genetically similar to you, as a way of ensuring survival of the species.
He became depressed at the implications and attempted to prove his theory wrong by committing random acts of kindness.
He gave away many possessions and eventually was evicted from his home. Unable to help homelessness, and unable to prove his theory right or wrong, he committed suicide.
Just a fun little story.