Why this word is great
VAGARY — [Noun] An erratic, unpredictable, or capricious action, occurrence, or idea. From the Latin vagārī ("to wander"), from vagus ("wandering"). Unlike "caprice," which springs from a sudden internal whim, or "fluctuation," which implies a measurable oscillation between known states, a vagary is an inexplicable, external swerve in the world's own logic. It is the freak hailstorm that shreds the May blossoms, the rogue wave on a calm sea, or the single, unbidden memory that reconstitutes an entire afternoon. The world is less a mechanism than a wanderer, prone to its own fits of absent-mindedness.