Hashem is the ultimate maitiv, benefactor. He created and gave us a world full of pleasure and kindness, so that we could recognize Him, and gain eternal enjoyment in olam haba by doing so.
So not only are our lives created to be happy, they are a means to the end of being eternally, nearly infinitely happy.
And there is just the right balance between the ability to see and experience that happiness, and the nature of human beings to focus on the negative, and not appreciate that kindness.