How did this morbidly obese alpha-nerd with no redeeming qualities suddenly find himself in an affair with his ten years younger, hot, married with children best friend? The reason might surprise you.
The tail plumage of peacocks for example is the opposite of advantageous in everyday life. But since it's sexually selected for (peahens like a showoff with a big tail-fan as a sign of fitness), it's advantageous for reproduction.