Kindness is beautiful. There are so may small acts of kindness you can perform every single day just by being aware of the needs of people around you. The best part about kindness is that nothing is lost, you gain from God just as others gain from you.
Proverbs 11:17 -- "Your kindness will reward you, but your cruelty will destroy you."
However, even when we are sad or happy, if we are conscious of how our words and actions affect others we are being kind. This generous, merciful way to respond to others is the way God would have us treat others - with love.
2 Thessalonians 3:13 -- "As for the rest of you, dear brothers and sisters, never get tired of doing good."