I don't know the key to success, but the key to failure is trying to please everybody.
Bill Cosby

You know the only people who are always sure about the proper way to raise children? Those who've never had any.
Bill Cosby

When you become senile, you won't know it.
Bill Cosby

Sure it's a big job; but I don't know anyone who can do it better than I can.
John F. Kennedy

Let every nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe to assure the survival and the success of liberty.
John F. Kennedy

Nobody cares how much you know, until they know how much you care.
Theodore Roosevelt

When they call the roll in the Senate, the Senators do not know whether to answer "Present" or "Not guilty."
Theodore Roosevelt

To achieve, you need thought. You have to know what you are doing and that's real power.
Ayn Rand

I love those who do not know how to live for today.
Friedrich Nietzsche

Faith: not wanting to know what is true.
Friedrich Nietzsche

There are horrible people who, instead of solving a problem, tangle it up and make it harder to solve for anyone who wants to deal with it. Whoever does not know how to hit the nail on the head should be asked not to hit it at all.
Friedrich Nietzsche

When one has finished building one's house, one suddenly realizes that in the process one has learned something that one really needed to know in the worst way - before one began.
Friedrich Nietzsche

I do not know what the spirit of a philosopher could more wish to be than a good dancer. For the dance is his ideal, also his fine art, finally also the only kind of piety he knows, his "divine service."
Friedrich Nietzsche

Perhaps I know best why it is man alone who laughs; he alone suffers so deeply that he had to invent laughter.
Friedrich Nietzsche

Today I love myself as I love my god: who could charge me with a sin today? I know only sins against my god; but who knows my god?
Friedrich Nietzsche

I hear, I know. I see, I remember. I do, I understand.
Confucius

If we don't know life, how can we know death?
Confucius

When you know a thing, to hold that you know it, and when you do not know a thing, to allow that you do not know it - this is knowledge.
Confucius

Real knowledge is to know the extent of one's ignorance.
Confucius

To know what is right and not to do it is the worst cowardice.
Confucius