Why do you feel good after giving something to someone else?
The brain has a neural structure responsible for incentive salience, or a motivation for feeling a certain kind of pleasure, derivated from specific activities.
They are classified in Primary Rewards, or associated with your instincts and primary needs for surviving as a human being, then the intrinsic rewards and extrinsic rewards, defined as a inner or outer pleasure generated by themselves.
So, giving action activates extrinsic brain reward system inside of you, produced after you gave something, maybe money, love, some stuffs, charity, etc. The importance of giving makes you happy and a better person, your brain gets healthy and develop good behaviours in a daily basis.
I am sure at least once in your life you´d heard "It is better to give than to receive", and for many others reason it is, but I guarantee you the next time you give something you will end happier than before.
"You are not deppresed, you are distracted". Facundo Cabral.
Good job but could use some citations for people to learn more about this topic!