It's not whether the glass is half empty or half full, it's who is pouring the water. The key in business and success at any endeavor is doing your best to control your destiny. You can't always do it, but you have to take every opportunity you can to be as prepared as-and ahead of-the competition as you possibly can be.
In true natural selection, if a body has what it takes to survive, its genes automatically survive because they are inside it. So the genes that survive tend to be, automatically, those genes that confer on bodies the qualities that assist them to survive.