Uttering "Oh ****" with a nervous pax listening
That's part of my passenger briefing:
"Don't worry if I talk to myself from time to time. This is the habit one gets into of explaining what one is doing to the instructor, many pilots do it.
"And if I swear at myself it's also probably nothing to worry about - it probably means that I'm irritated that I've done something slightly less neatly than I think I should be capable of."