It is dangerous to be sincere unless you are also stupid.
George Bernard Shaw (1856-1950) 

It takes a lot of time to be a genius, you have to sit around so much doing nothing, really doing nothing.
Gertrude Stein 

Know thyself.
Linnaeus 

Knowledge comes, but wisdom lingers.
Lord Tennyson 

Knowledge is limited.
Albert Einstein (1879-1955) 

Knowledge may give weight, but accomplishments give luster, and many more people see than weigh.
Earl of Chesterfield

Let us be thankful for the fools. But for them the rest of us could not succeed.
Mark Twain (1835-1910) 

Life is a succession of lessons enforced by immediate reward, or, oftener, by immediate chastisement.
Ernest Dimnet 

Live your questions now, and perhaps even without knowing it, you will live along some distant day into your answers.
Rainer Maria Rilke 

Look alive. Here comes a buzzard.
Pogo  , character in "Pogo," comic strip by Walt Kelly