After Lucy and Linus leave, Schroeder is shown playing the piano with the music score at the top of the screen. As he's playing Lucy's head appears in between the bass and treble staffs leaving him to pause playing and ask rhetorically, "Don't tell me I've grown accustomed to *that* face." This was used previously in Play It Again, Charlie Brown (1971).
This special shows one of the rare times Linus could go without his security blanket.
The special is adapted from a storyline from the comic strip that lasted from May 9 to May 21, 1966.