Oh my gosh you guys I just realized that when Melody asked who River is, the Doctor says "Spoilers" because he's remembering all those other times he met River, but that's the first time she meets him, so all those times she says "spoilers" she's quoting him, and all those times he says "spoilers" he's quoting her!!!! <-- Mind. Blown.
Snape has to be one of the most mysterious, complicated characters I have ever read about. He might be twisted and cruel but he is that way for a reason. I don't think Snape was ever supposed to be labeled as "good" or "bad". I think he was there to show you that there may be an in between. The character is just so fascinating and I love him to pieces.