Onions make you cry because they remind you that your own identity, your "self," is as ill-defined as the core of an onion. In a quest to slay inferior selves in order to perfect our own lives and come out as our own ideal person, are we simply peeling back layers of onion, searching for a core? The core, you see, is naught but more small layers - or, perhaps, a point from which concentric layers begin to radiate. Decide for yourself where its boundaries lie.
Henrik Ibsen's Peer Gynt makes extraordinary effort to stay true to himself. When the fellow finds himself starving in the forest, he digs up a wild onion and begins to peel back its layers. Each one, he remarks, is a different stage of himself throughout the play. Where is the core, the thing he's been seeking through the entire story?
I could say that it's not there. I would rather say that it's there, and up to us to define.
No onion ever made me cry as much as the budding vidalia I found with two cores.