To dominate, adapt, survive better than others? Any life form has for only purpose to adapt, survive, nothing else. We re not designed to be happy per se, but to adapt, survive, just like every others life forms. Surviving, adapting creates "hapiness" in our brain, knowing you have superior odds of survival makes you feel good. Low odds of survival and difficulties to adapt make you suffer mentally, emotionally. We re designed to adapt at all costs and being able to adapt to difficulties is what makes us feel happy. No challenges, no difficulties during childhood makes kids once they become adults depressive whenever they face a difficulty. Basically suffering gives its meaning to feeling good and vice versa hence the impossibility to be constantly happy. We re just animals just like any other kind of animal life form/specie on earth. Dominating and knowing we will dominate in the future is what makes us "happy", produces chmicals of hapiness in our brains. Some life forms -mostly females in animal species- survive by submitting themselves to males to be protected.