Had to slightly change the title of this one, since "Knife" isn't really an emotion.
Having decided to take Lenny Leonard's advice and simply cut Bart's throat, Bob crept into Bart's room while the boy was brushing his teeth, and lay in wait behind the door. While imagining the impending murder, he remembered the time he'd come into Bart's room on the houseboat while wielding a machete, and the other time that he'd held a switchblade to Bart's neck on the Wright Brothers' plane. It was sort of darkly amusing that a little boy who'd just been kidnapped by his mortal enemy and in imminent danger could care that bugs were getting stuck in his teeth.
Bob decided that his preference was for the carving knife that he currently had, but couldn't quite figure out why. Maybe it was easier to carry than the machete, yet not too small, or maybe it just appealed to his more theatrical side.
While Homer and Bart were having their little sappy moment after Homer tucked Bart in, Bob briefly considered not going through with this...but dismissed the thought as being a lingering side-effect of the rhino tranquilizers from this afternoon.