You've got to get obsessed and stay obsessed

What's here is only the beginning, the springboard for ten thousand flights of fancy. As you say, there are so many different angles, so many varieties of bastard, so many second chances he never got to take, so many of Snape's regrets and petty triumphs and late-night thoughts and unfinished projects. The friendships he never had. The brilliance that died with him. He's a difficult character to write (because a Snape who isn't difficult seems OOC to me), but that's why I keep circling back, desperate to figure out how he might pay the price and still walk away.