To prevent illness in later life, you should never have been born at all.
Success does not consist in never making mistakes but in never making the same one a second time.
A life spent making mistakes is not only more honourable, but more useful than a life spent doing nothing.
Some men see things as they are and ask why. Others dream of things that never were and ask why not.
The power of accurate observation is frequently called cynicism by those who have not got it.