Quality is not an act, it is a habit.
I can, therefore I am.
Be thine own palace, or the world's thy jail.
Know or listen to those who know.
Be gentle to all and stern with yourself.
Begin to be now what you will be hereafter.
Things do not happen. Things are made to happen.
What you do today can improve all your tomorrows.
Never complain and never explain.
Be kind whenever possible. It is always possible.
A serious and good philosophical work could be written consisting entirely of jokes.