A rare piece of cartoon metaphor here, as Patty's words literally diminish Charlie Brown in stature. I think this is probably the only strip which does this. Schulz must have been dissatisfied with this solution, as later strips show embarrassment using cross-hatching to represent blushing.
Snoopy's smug look in the last panel is a winner. There are strips where Snoopy just sits there smiling, uncomprehending, like a real dog, and there are strips like this one where he has more of a personality. Not close to Snoopy's later brilliance, but still, a step along the way.