That is shortsightedness

Actually we face many dead ends in life when we presume that there is only one way to proceed.

If one is thirsty he can drink water or milk or fruit  juice.. or many other liquids according to availability and, if possible, to suit his  taste too.

But people tend to insist that only water or milk or juice as the case may be should quench the thirst.

That is shortsightedness