pphaneuf talks about being happy and how it's more important for him to make himself happy than to dilute all his energy trying to make everyone else happy... and yet, how he just wouldn't be happy if everyone else was unhappy, and other people being happy leads back to him being happy.
This is a classic compromise situation. The correct solution is not simply to sacrifice your own happiness for others' happiness, or vice versa, or to alternate randomly between them, but to find a way for one to lead to the other.
That's not actually very hard to do, in concept, at least. You have to find the root cause of the unhappiness and then fix it. Looking at it from such a high level automatically handles confusing issues like "Should I have some temporary unhappiness now for greater happiness later?" or "Should I be a little less unhappy now so that this person can be happy now so I can be happy later?" The underlying strategy - solving the root cause - can guide all your specific actions.