I think a lot of pilots chuck away a lot of what would be their normal planning decision rules when they fly with somebody who they think knows what he's doing. Might even happen with two plain PPLs because each may think that the other one would "say something" but neither says anything to the other.
Couldn't agree more, IO. Been there, done that and got the (sweaty) T-shirt.
Btw, I do the same as SNS3, i.e. say everything I do aloud, my first instructor taught me that. He claimed it helps as a sort of 'self-challenge-and-response', and I'd agree.