Why does everything hafta go by threes?
It’s like, not a completed cycle unless you’ve got a third to throw up there. And three is a strange, awkward number. But maybe it kind of gives people enough options to have a preference, to have a favorite; to choose a little order, organize a mini-hierarchy, set up a pyramid scheme, impress strangers with your dearth of evil step-sisters, set-up a precedent for bears, stooges and ill-fated blind mice.
Three is enough to be jovial, and the perfect equation for drama.
Aw shit, I went and answered my own question.