What did you learn on Launch Day that you wish you'd known before?

The 24 hours of launch day is intense. Time seems to race by, with not enough time to do all the things you'd planned. I'd love to know what's the one most important thing you realised on launch day, that you wish you could turn back the clock and do again, or prepare better in advance. I'd love to hear your experience? We're in the middle of our 24 hour launch and there's loads of things I'm only learning now, that would have been so helpful to already know!