Very well put, Turnbull. On the surface, Fredo seems blithe and uncomplicated. As the film progresses, we become privy to the inner turmoil that's been secretly troubling him. It's another illustration of the psychological depth Coppola infused in the characters.

And, is in reality, Fredo probably carried on with this buildup of indignities until it gradually reached the level of discomfort. He probably wasn't initially sure of what was bothering him until his psyche eventually articulated it for him.

And to think all this fascinating character insight started with a question about a harmonica . AppleOnYa, if you're reading: See, posts about minutiae and minor details ARE valuable in these forums. They can lead to MAJOR discoveries .