Peanuts by Charles Schulz for September 21, 1965
Transcript:
Snoopy dances.<BR><BR> Lucy says, "You wouldn't be so happy if you knew about all the troubles in this world!"<BR><BR> Snoopy keeps dancing and thinks, "Don't tell me . . . I don't want to know . . ."<BR><BR> Snoopy dances and thinks, "I'm outrageously happy in my stupidity!"<BR><BR>
This must be before the term “ignorance is bliss” came into being.