Happiness is an internal MEASURE of our success. It can only be a secondary goal. We can use happiness to decide if the rest of our existence is going well or badly. The true motives of mankind? Survival, always survival. But how do I know that I am acting consistently with those motives?
I am happy today because I have no snarling wolves at the door, food is in the pantry or the fridge or the freezer, nobody is particularly sick, and my step-kids respect me. The grandkids love me. The bills are paid. The doctor hasn't given me a pronouncement of "x months to live."
We can strive for happiness, but that old phrase comes to mind: "Money can't buy happiness." True, but if you apply that money to the wolves at the door, the grocery and pharmacy, the house and kids and spouse, and some entertainment, you can feel fairly happy anyway. It isn't how much money you have; it is how well you use it. Part of that old theory of value through utility: Nothing that does nothing has intrinsic value. Which is why buying gaudy trinkets and baubles is often a waste of money unless your "utility" is the expressed intention of making someone die in a fit of jealousy that you have that much money to waste on stuff that you can't eat and that, as something wearable, doesn't cover very much skin.