To be kind is to hope for and work toward a better world. When you are kind you do not naturally receive some “reward”, but rather give a “reward” to those you provide kindness to. The catch is that your kindness will affect a great many more than you will ever know or hear about. It is multiplied. You, every single day, benefit from the kindness of others whether you are aware of it or not. Kindness is not transactional. You give comfort and ease to those around you. The closest it gets to a transaction is that you may hope that by being kind you plant a seed in others that will grow into kindness of their own, which may in time find its way back to you.
Metaphorically, imagine a communal food pantry, where the food actually represents some abstract stockpile of kindness and goodwill in the world.
To be neutral is to bring a foodstuff you are less fond of, and take a foodstuff you are more fond of.
To be kind is to bring plentiful foodstuffs for others to enjoy, and take only what you need.
To be unkind is to take when you do not need it.
I know people have already hit you with the “kindness is its own reward” but it truly is. When I consider the profound impact on my own life because of the kindness of others, I am given the drive to try and provide that for others. What a joy it is to know that I may have helped someone get through their day just a little bit easier.
We cannot control the evils of others, but we can control the kindness of ourselves, and kindness can ease the pains caused by the evils of others.