Thanks for this Macanudo to Kilby, who says ‘The moon doesn’t look “happy” to see friends drop by, the eyebrows and wrinkles make it look distinctly “worried”.’
Also he gives a reference example of a smiling full Luna — though not the classic comics one he wanted to locate.
Comics I Don't Understand 
Having these self-identified “lunatics” turn out to mean friends of the Moon is a nice move, that should qualify this as an OY.
@ Dana K – Even though I didn’t actually suggest “OY” when I submitted this, Mitch made the correct identification when he posted it (see the category tags above).
The moon isn’t happy because the witches aren’t friends, but “lunatics” – fanatics of the moon. They probably come by uninvited asking for autographs – and the moon doesn’t have hands to sign autographs.
They’re lunatics, and nobody likes ticks.
These late-18thC people in Birmingham (West Midlands, not Alabama) referred to themselves as “Lunaticks” – it was called the Lunar Society not because they studied or were friendly with the Moon but because they “would meet during the full moon, as the extra light made the journey home easier and safer in the absence of street lighting.”
https://en.wikipedia.org/wiki/Lunar_Society_of_Birmingham
Hm, to me, the moon looks rather neutral, not unhappy. More like “Ah, it’s the girls again. Nice for them to show up from time to time.” I did not expect a full happy moon face (that would be strange). Judging from the art style, if the artists wanted to convey “unhappy”, the moon would be seriously distorted, not vaguely “not full on happy”.
So, just the gag would just be the juxtaposition of the word “lunatic”.
I thought that the moon should be glad to have a couple of enthusiastic groupies, even if they are a little bit crazy.