|People are complex forms of life. People are born as individual, independent, reasons to exist. As instinct is a biological reason to live in simple form, so is happiness a biological reason to live in complex form.
Happiness leads to creativity as complex life forms (reasons to live) can then invent new ways to be happy, and invent new ways to prevent those complex processes that destroy those reasons to live, whereby those complex processes are labeled as sadness, depression, and many other forms from simple to complex.
Creativity is the biological adaptation power built into the form of life (reason to live) known as people, or humans. So these complex reasons to live are thereby empowered with the ability to improve the reasons they share to continue living. Each individual reason to live, each human, can share new and improved reasons to live, richer, happier, fuller, and greater complex reasons to live added to the base, simple, fundamental, instinctual reason to live.
Creativity as the adaptive complex adaptation to forms of life can be inspected with much greater detail as to what was the process by which simple instinct was in some way empowered to become creativity in specific forms of life as life grew from simple to complex forms.