I have quite a few:
"Life is a tragedy for those who feel and a comedy for those who think"
"Finish each day and be done with it. You have done what you could; some blunders and absurdities have crept in; forget them as soon as you can. Tomorrow is a new day; you shall begin it serenely and with too high a spirit to be encumbered with your old nonsense."
"Let go of your attachment to being right, and suddenly your mind is more open. You're able to benefit from the unique viewpoints of others, without being crippled by your own judgment.
-- Ralph Marston"