In the last season of BB, Walt and Jesse are setting up the train heist. Walt comes home all dirty and dusty to which Skyler wryly asks, "Out burying bodies?" There's a beat and then Walt replies, truthfully, "Robbing A Train," and walks off. Knowing it's almost certainly not a joke, Skyler's face gives a little, "Huh. Well, I guess I didn't see that coming."
It's just a tiny scene, but for the point where all of the characters are in the show, it's just so perfectly done.