I've started on the wrong song enough times that it was no longer embarrassing.
I came down to the altar from my music perch for Communion, in that "condition." The man who noticed it and helped me become aware, unfortunately, had an artificial larynx so there was no way he could speak softly!
As long as we're in this territory, I'll recount a self-inflicted "embarrassment" -- the most heroic thing I have ever done in my ENTIRE life! An evangelist had just finished ministering; he was dealing with an intestinal cancer himself, and as he sat down he ripped a loud one - brrrrrrump! with a little squeal at the end. He was absolutely stone-faced; but sensing that someone had to take responsibility, I hunched my shoulders and gave a little embarrassed look; a few people caught my eye, and I went home proud that I had taken one for my friend.