I’m often reminded of a SpaceX render they put up on the 'Tube back when they were still working out the reusability thing. Commenters had a lot of questions about how the particular flight plan impacted on their fuel budget. And so, Elon himself waded in with the answers. Except he was talking about the dollar price it cost to buy the fuel. He was like ‘why are you worried about fuel, it’s not that expensive, guys’ because he didn’t understand the questions. He didn’t understand why the amount of fuel and the mass of the fuel would be significant to anybody. Guys, I think he doesn’t understand the rocket equation. He doesn’t understand the central problem of rocketry. I think the guy might be full of it.