My favorite is the one attributed to Eleanor Roosevelt

Life is made up of marble and mud.
Nathaniel Hawthorne

It is not length of life, but depth of life. 
Ralph Waldo Emerson

Nothing in life is to be feared; it is only to be understood. 
Marie Curie

He that would live in peace and at ease, must not speak all he knows or judge all he sees. 
Benjamin Franklin

Life is short, art long, occasion brief, experience fallacious, judgment difficult. 
Hippocrates

Tell me who admires and loves you, and I will tell you who you are. 
Antoine de Saint-Exupéry

We are always the same age inside. 
Gertrude Stein

History, like beauty, depends largely on the beholder. 
Desmond Tutu

No one can make you feel inferior without your consent. 
Widely attributed to Eleanor Roosevelt

The act of dying is one of the acts of life. 
Marcus Aurelius

To love oneself is the beginning of a lifelong romance. 
Oscar Wilde

There is a crack in everything. That’s how the light gets in. 
Leonard Cohen

Brevity is the soul of wit. 
William Shakespeare

Travel is fatal to prejudice. 
Mark Twain