I kinda caught on to the Snape/Lily dynamic through the books and movies. He always went out of his way to badmouth James in the books and never said a bad thing about Lily, and in the very first movie, when he first laid eyes on Harry, that look on his face wasn't disgust to me, it was wonder, b/c for the first time in 11 years he was seeing her eyes again. (Then again, Alan has that effect on me )