Shoot for the moon...

Shoot for the moon. Even if you miss, you'll land among the stars.

--Les Brown

A wise man is cured of ambition...

A wise man is cured of ambition by ambition itself; his aim is so exalted that riches, office, fortune and favour cannot satisfy him.

--Samuel Johnson

A person who aims at nothing...

A person who aims at nothing is sure to hit it.

--Anonymous