It is all a matter of quantity.
It is for first and foremost a matter of quantities. Examples are abundant. An engine will not ignite if its battery power drops below a certain voltage. A spaceship will not reach its orbit if does not carry the minimum amount of fuel needed for reaching it, and I want to believe that in most cases a student will not be accepted at a university department if his score is below the minimum set by that department. Many processes are like that. For me this is quite unfortunate, because it means that I will not win the Noble Prize, or even not a very noble one for that matter.
Why? Simply because my life is very short, compared to human stupidity.