My Bloody Valentine shows us that Sam is starved for blood/vitality/POWER, Cas craves āthe strange fleshā/meat/SEX, and Dean, ofc, is all about LOVE.
Blood, especially in Christian terms, is vitalityāa stand-in for the forbidden consumption of Godās power.
Beef may be a clean animal, but the episode foregrounds meat as desire: the opening scene with the couple tearing into each other underlines the meat/sex consumption that Cas embodies.
And then thereās Dean and LOVE. He explicitly rejects the Cupidās (rightly suspicious) account of his parentsā story. More than that, Cupids themselves are framed as random, glib facilitatorsāeven outside Heavenās āimportantā matches, they cheapen feelings into machinery. Dean refuses that. He needs to believe in LOVE, and it is LOVE he craves to fill the emptiness.
