It's not that I'm so smart, it's just that I stay with problems longer Eighty percent of success is showing up I respect faith, but doubt is what gets you an education The greatest obstacle to discovery is not ignorance, it is the illusion of knowledge The pessimist complains about the wind, the optimist expects it to change, the realist adjusts the sails If you don't make mistakes, you're not working on hard enough problems. And that's a big mistake You can never get enough of what you don't really need Insanity doing the same thing over and over again and expecting different results Do not confuse motion and progress. A rocking horse keeps moving but does not make any progress I don't know the key to success, but the key to failure is trying to please everybody