Even Experts Can Get Complacent

Massad Ayoob did, but fortunately it was within the environs of a competition, rather than a real life scenario:

With the less recently familiar Brand B gun, I was focusing on its subtleties. Its grip to barrel angle was slightly different than what I’d been lately habituated to, as was its trigger reach and length of trigger reset. I was running Conscious Competence pretty much every shot. With Brand A, the old familiar extension of the hand, I found myself going auto pilot and taking overconfident liberties. There were stages where I KNOW I relaxed my grip, where I pointed rather than aimed, where I rushed instead of pressed the trigger.

Where I took my familiar gun, and my supposed skills with it, for granted.