„Demetrius: Villain, what hast thou done?Aaron: That which thou canst not undo.Chiron: Thou hast undone our mother.Aaron: Villain, I have done thy mother.“

— William Shakespeare
„Oh, Diamond! Diamond! thou little knowest what mischief thou hast done!“
— Isaac Newton
„Let not thy mind run on what thou lackest as much as on what thou hast already.“
— Marcus Aurelius
„Think not so much of what thou hast not as of what thou hast: but of the things which thou hast, select the best, and then reflect how eagerly they would have been sought, if thou hadst them not. At the same time, however, take care that thou dost not, through being so pleased with them, accustom thyself to overvalue them, so as to be disturbed if ever thou shouldst not have them.“
— Marcus Aurelius