Okay, okay, okay, this is probably deeply off-track, but all I can think of is Harry––who upon learning that Snape, of all people, his pain in the neck potions professor knows his aunt––has now received what can only be called a psychic punch to balls.
How, how, how, is a teenage boy supposed to rectify this, mentally? Connect these strange unjoined worlds to somehow explain that Snape––Snape!––knows his Aunt Petunia?
“It doesn’t make any sense, mate,” Harry tells Ron, blearily, desperately wishing at age thirteen years that his butter beer was a real beer. “It just––it can’t be. Why would he know Aunt Petunia?”
Ron grimaces. “Why would he want to? I mean, I know he’s Snape, and all that, but––”
Harry writes his only letter back to #4 Privet Drive, dotted with tears, and it has one line: How do you know Severus Snape?
Petunia writes back: DO NOT MENTION THAT MAN EVER AGAIN.
And this. This. Sparks a light in Harry’s head. This is the same way Petunia talks about celebrities who have deeply, personally offended her. Usually when she fancied them and then they got married. It’s so completely clear to him, now: Snape is deeply, irrevocably, utterly in love with Aunt Petunia.