Because happiness is a nominalization one of the insights that NLP has, is that you do happy rather than be happy. For most people happiness is too big. Also, unlike many people think happiness is not high up in people’s hierarchy of values.
The new passion. – Why do we fear and hate a possible reversion to barbarism? Because it would make people unhappier than they are? Oh no! The barbarians of every age were happier: let us not deceive ourselves! – The reason is that our drive to knowledge has become too strong for us to be able to want happiness without knowledge or the happiness of a strong, firmly rooted delusion; even to imagine such a state of things is painful to us! Restless discovering and divining has such an attraction for us, and has grown as indispensable to us as is to the lover his unrequited love, which he would at no price relinquish for a state of indifference – perhaps, indeed, we too are unrequited lovers! Knowledge has in us been transformed into a passion which shrinks at no sacrifice and at bottom fears nothing but its own extinction; we believe in all honesty that all mankind must believe itself more exalted and comforted under the compulsion and suffering of this passion than it did formerly, when envy of the coarser contentment that follows in the train of barbarism had not yet been overcome. Perhaps mankind will even perish of this passion for knowledge! – even this thought has no power over us! But did Christianity ever shun such a thought? Are love and death not brothers? Yes, we hate barbarism – we would all prefer the destruction of mankind to a regression of knowledge! And finally: if mankind does not perish of a passion it will perish of a weakness: which do you prefer? This is the main question. Do we desire for mankind an end in fire and light or one in the sand? –
Daybreak paragraph 429
The Joyless Person. — A single joyless person is enough to make constant displeasure and a clouded heaven in a household ; and it is only by a miracle that such a person is lacking! — Happiness is not nearly such a contagious disease; — how is that?
Gay Science paragraph 239