This is one step away from not having any supernatural component to your explanatory scheme at all. Given the marginal explanatory efficacy of 'God' (Because God did it!; Because God said so; etc.) and all other such posits above and beyond accepted science is approximately zero, you might as well drop them like most reasonably intelligent people do, most prominently in this context virtually all of the evolutionary biologists you are reading (or ought to read).
I believe it's about survival of the fittest, as obviously being extremely smart doesnt actually keeps you alive, it somewhat makes you loose the will to live/fight realizing how vain our animal existence is intrinsically, especially considering our species has no other fate but disapear/evolve after a while. So a happy person just focus daily on blindly killing instead of being killed, using -blindly again- all the inherited or acquired strategies of survival he/she can. Being successful, beating the competition, makes one feel "happy". Failing to do so, makes one "unhappy". There is no justice or possibility for "equality", empty words, so it's all about enjoying killing others with what you have , with no remorse, and using your anger against them to better dominate them. If it works, it means God is on your side. If it doesnt it means he wants to punish you.
Still, it doesnt mean there is no God, again. In fact, it is exactly how the Bible tells you to live; a balanced life following rules that benefit the whole as long as everyone follow them, playing the same game. Bible doesnt tell us to be peaceniks and end like buddhists, it actually teaches us to use revenge and all our capacities to better dominate others. As long as it works and you follow God's words, it means you are "right" doing so.
I personally dont see God as a man in the sky, but more like an eternal life form who s the epitome of evolution, can survive everything everywhere in the universe, probably can create life, the ultimate survival machine that keeps life going on.
All very smart people need love and a reassuring daily routine, to fit in society doing "normal stuff" or they end using their brains to kill, destroy a world that rejects them. Everything men do has no more intrinsic value than what say, ants, do. You can come to this conclusion using science, but it is also a humble spiritual realization at the same time.