Following XYZ religion? whats the point, unless it makes you happy?
Saving children from starvation? Whats the point, unless it makes you happy?
Having 2.1 children and a white picket fence? Whats the point, unless it makes you happy?
You are frustrated that you're happiness seeking is never "finished". This is because you are viewing happiness as the result of efficient causes, like something that follows mechanical processes. The happiness that results from efficient mechanical causes, is indeed chemically fleeting. The more metaphysical end of "contentment", is not something that simply represents the end of an efficient cause.
1. Every time you get frustrated at your current happiness being fleeting: its rather like following the north star, and getting upset that you "havent gotten there yet".
2. People do however, get to meaningful places by following the north star. It doesnt matter that you never "get to the north star".
3. So to relate back to happiness: dont get frustrated with the efficient ends of happiness, keep your eyes focused on the final ends of happiness, and let that final end be a star that guides you through the small transient efficient ends here on earth.