Why does happiness matter in software engineering?

I believe in a threshold of intelligence and skill in software engineering after which happiness becomes a primary factor in accomplishment. The very best engineers need breathing room in which to be creative and innovative. Happiness matters in software engineering because it gives those engineers the space in which to be mindful and open to unusual connections and combinations of ideas.

Good engineering requires mindfulness. This represents a fundamental believe in the intelligence of human beings.

My theory: intelligence + experience + mindfulness = excellent engineering