“My mentality is that of a samurai. I would rather commit seppuku than fail.”

“I have made the mistaken assumption - and I will attempt to be better at this - of thinking that because somebody is on Twitter and is attacking me that it is open season. And that is my mistake.”

“I started SpaceX with the expectation of failure.”

“Even if producing CO2 was good for the environment, given that we're going to run out of hydrocarbons, we need to find some sustainable means of operating.”

“Optimism, pessimism, f**k that; we're going to make it happen. As God is my bloody witness, I'm hell-bent on making it work.”

“Assume a virtue if you have it not.”

“Best men oft are moulded out of faults.”

“Mend when thou canst; be better at thy leisure.”

“We are advertis'd by our loving friends.”

“No, no; 'tis all men's office to speak patience To those that wring under the load of sorrow, But no man's virtue nor sufficiency To be so moral when he shall endure The like himself. Therefore give me no counsel: My griefs cry louder than advertisement.”

“Beware Of entrance to a quarrel; but being in, Bear't that the opposed may beware of thee. Give every man thy ear, but few thy voice; Take each man's censure, but reserve thy judgment. Costly thy habit as thy purse can buy, But not express'd in fancy; rich, not gaudy; For the apparel oft proclaims the man.”

“I have been studying how I may compare This prison where I live unto the world; And, for because the world is populous, And here is not a creature but myself, I cannot do it. Yet I'll hammer it out.”

“Retire me to my Milan, whereEvery third thought shall be my grave.”

“I have neither the scholar's melancholy, which is emulation; nor the musician's, which is fantastical; nor the courtier's, which is proud; not the soldier's which is ambitious; nor the lawyer's, which is politic; nor the lady's, which is nice; nor the lover's, which is all these: but it is a melancholy of mine own, compounded of many simples, extracted from many objects, and indeed the sundry contemplation of my travels, which, by often rumination, wraps me in a most humorous sadness.”