Ah, humans, aren't we clever? We've been moulded and primed over millions of years of evolution into the temple-building, space-faring, technologically advanced apex predators that we are. So why do we sometimes go into the kitchen and forget why we're there?
It turns out that evolution is not the perfect process we would have hoped, and that there are some infuriatingly simple things that we just plain suck at. Evolution is less of a steady progression to perfection and more of a "wing and a prayer, trial and error, let's just try things out and see what sticks" kind of deal. In fact, there are many examples of other, "simpler" species that far outstrip us in certain fields.
Ironically, some of the things that we're bad at are actually a result of our technological advancement. The human brain evolved when we were hunting on the open plains of Africa, not checking our emails on the tube, and so far hasn't really had much time to make its adjustments. Our lifestyles have developed way quicker than our poor old brains and we have achieved the evolutionary equivalent of sticking your great-great granddad in the cockpit of a Boeing 747 and telling him to fly it.
So, ready to find out how much you suck at stuff? Always fun.