Full Idea
Happiness is found to be something perfect and self-sufficient, being the end to which our actions are directed.
Clarification
'Happiness' is the Greek word 'eudaimonia', also sometimes translated as 'flourishing'
Gist of Idea
Happiness is perfect and self-sufficient, the end of all action
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1097b21)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.74
A Reaction
This will be eudaimonia, so while this sounds like an announcement of the secret of life, eudaimonia is only really a placeholder for things going very well, in some way or other.