"Impossible is just a big word thrown around by small men who find it easier to live in the world they have been given than to explore the power they have to change it.  Impossible is not a fact, it's an opinion.  Impossible is not a declaration, it's a dare.  Impossible is potential.  Impossible is temporary.  Impossible is nothing.”. Mandela

I seems that a little green frog had fallen into a rut in a road and could not quite jump high enough to get himself out.  His frog buddies were at the top of the ditch urging him on. 

“Come on! You can do it!” they would all yell in unison at the top of their frog lungs.  The Little frog would jump as hard as he could, but he just could not jump high enough, despite everyone’s encouragement and advice.  After two hours, the frog was still in the rut and his buddies could wait for him no longer. They went hopping away without him. 

Later in the day, just as they were getting ready to swim in the lake and do some croaking, the frogs saw their little buddy who had been trapped in the rut.  Figuring that he would never get out of there, they excitedly exclaimed, “What happened? How did you get out of the rut?”  The frog turned to them and said, “A big truck came down the road and I HAD to get out!”

From Advanced Rhinocerology by Scott Alexander