“That’s ok, I’ll do it [better/smarter/with more energy/classier] next time.”
Here’s the newsflash: Next time doesn’t always exist. In fact, I would argue that the more important something is, the more impactful it could be, the less number of tries you’ll have it.
Try telling the Olympic athlete that didn’t put everything they had into training that they’ll do better next time.
Don’t wait for next time. Don’t chicken out and half ass it. If you need to do it twice, then do the “first time” ahead of time – visualize it or practice it. I don’t care what “it” is – the truly great opportunities are few and far between… and some are never again.