Nothing we do can make God any happier than He already -- or rather, eternally -- is. Nothing we do can make God any less happy. Pious sentimentalism aside, there are no Divine feelings to be hurt, no Divine pain to be eased.
Strictly speaking, we can't act for God's good. Since acting for another's good is the meaning of love, how can we love God?
By loving our neighbors, of course. St. Catherine of Siena explains it this way, writing from God's perspective:
I wish also that you should know that every virtue is obtained by means of your neighbor, and likewise, every defect; he, therefore, who stands in hatred of Me, does an injury to his neighbor, and to himself, who is his own chief neighbor....
Thus, every act of help that [a man] performs should proceed from the charity which he has through love of Me. And every evil also, is done by means of his neighbor, for, if he do not love Me, he cannot be in charity with his neighbor; and thus, all evils derive from the soul's deprivation of love of Me and her neighbor; whence, inasmuch as such a man does no good, it follows that he must do evil.
The fact that we have neighbors to whom we can do good, and thereby express our love of God, is a mark of God's love for us.
The clearest sign of God's love for us is, of course, Jesus. In the Incarnation, we are given a Neighbor above all other neighbors to love. Our human love for the man Jesus is the means above all other means by which we express our creaturely love for the Creator God. If loving the least of Jesus' brothers is loving the Lord our God, how much moreso is loving Jesus loving God?
Watch out, though, for the too simple syllogism, "I love the man Jesus. The man Jesus is God. Therefore, I love God." There's an equivocation here. Love for a man is not the same kind of love as love for God.
The equivocation comes from the statement, "Jesus is God," which is an unfathomnable mystery. Jesus is man and Jesus is God, but He is not man in the same way He is God. He is both man and God together, but since man and God are utterly unlike, the "is" in "Jesus is man" is utterly unlike the "is" in "Jesus is God."
What this means, moving the matter back to love for God and love for neighbor, is that, although these two loves cannot be separated, they aren't simply combined. It's not quite like the case of a man who loves what his lover loves because she loves it, but of a man who loves what his lover loves with his lover's love. Which is impossible, unless the Lover is God.
But it's the same mystery as free will, so I won't pretend to have a satisfactory way of expressing it.