Above all else, why would you ever worship anyone but Felicity ('happiness')? After all, if you are happy, you need no other gods nor care about anything else that might happen to you. If, on the other hand, 'felicity' is not a god, but is rather a gift of the true God, then no amount of worship of 'happiness' personified will ever make you happy. "If Felicity is not a goddess, because, as is true, it is a gift of God, that god must be sought who has power to give it... For he cannot be free from infelicity who worships Felicity as a goddess, and forsakes God, the giver of felicity; just as he cannot be free from hunger who licks a painted loaf of bread, and does not buy it of the man who has a real one."
The same of course is true today--everyone searches for happiness. In self help books, in drugs, in political and social engineering, in escapist literature, in, well, everything you could possibly imagine, we search for that which will bring us joy and delight. The problem is, true joy only ever comes from the God who created us through the shed blood of His Son. Until we stop pursuing happiness and start pursuing God we'll never find the happiness we all want. One of the best books ever written on this subject is Desiring God: Meditations of a Christian Hedonist (which admittedly can be a bit of a slog at times, but is always worthwhile in the end). If you have never spent time with John Piper, his website is a treasure trove that's far too easy to get lost in...
It's easy enough to see where the pagan gods come from--they are simply common objects or ideas personified by the mind of sinful man (and often not even given a different name).
The pagans seemed to have some understanding that true happiness came from the One true God, but they were mistaken in thinking that it was Jupiter. Even they seemed to know this since they came up with the goddess "Felicity" rather than simply leaving that with Jupiter himself.
Instead, we must look to the true God. He alone can satisfy if only we will be content in Him. "For him, I say, God the giver of felicity will not be enough to worship, for whom felicity itself is not enough to receive."