Simple things like speaking up in a crowd or a propensity for picking fights means you probably have a surplus in the nutsack department. By contrast, bolting from conflict, constanly caving to the wants of others, or shrinking like a violet in the face of almost anything can safely be assessed as having too little nutsack.
Through all the stages of life a man's nutsack dictates the pace. Humanity can ascribe unlimited meaning and spirituality to that which drives us or motivates us or defines us. But for men, I think it's all about our nutsack.
To go after the girl or stifle your heart's desire by hiding in plain sight. To turn into the current and swim hand over hand upstream, or concede to water's will, and drift aimlessly like a leaf to wherever the water flows.
Success is the risk-taker's reward; failure is the coward's yield. The bellwether is nutsack.