Riddle was, of course, well known throughout Hogwarts, favorite of many teachers and students, hated by few. Something about that smile wasn't quite sincere; something about that politeness was forced.
But no one said a thing, because you just didn't talk that way about Tom Riddle.
And one year he came back, and he seemed a bit less likable, the smile a bit less sincere, politeness a bit more forced. Only a few people said something, because you still shouldn't talk about him like that.
Minerva did. Because she was a Gryffindor, wasn't she, and she had to be bold.
AN: Did I abuse the italics a bit too much? Hm... Well, this is only sort of kind of focused on McGonagall, but I wanted to do it about Tom, because it seemed like something that would highlight her bravery. The others I'll be writing don't have the same situation, going to school with him, having classes with him, and I think that's a very interesting scenario. Did I still do well with this? I don't really know, but I do feel it's the best I can do with McGonagall.