Each morning when I open my eyes I say to myself; I, not events, have the power to make me happy or unhappy today. I can choose which it shall be. Yesterday is dead, tomorrow hasn’t arrived yet. I have just one day, today, and I’m going to be happy in it.
– Groucho Marx
The happiness of your life depends upon the quality of your thoughts: therefore, guard accordingly, and take care that you entertain no notions unsuitable to virtue and reasonable nature.
– Aurelius, Marcus