The one thing that matters is the effort.

How could there be any question of acquiring or possessing, when the one thing needful for a man is to become - to be at last, and to die in the fullness of his being.

The one thing you can control is effort.

Change is the one thing we can be sure of.

The one thing you can't do when you're highly ranked is relax.

Curiosity is the one thing invincible in Nature.