Have you ever talked to someone, and when you say a sentence, he/she'll take the last part of that sentence, make it a question right back to you, and maybe say mmm after it? Most of the time it's a women who does it. All of the time it's annoying.
I have had a conversation like this in the past. I don't know when. But I most definitely witnessed it on the train today and that's what made me think of telling you about it.
For example (didn't actually happen):
PERSON: Yeah, so I'm going for my BA at Emerson College.
LADY: Emerson College?
PERSON: Yeah, and then I'm thinking of heading out West, you know, get in touch with nature.
LADY: Get in touch with nature?
PERSON: Why are you doing that?
LADY: Doing that?
You get the picture. It's a weird thing and I don't know how common it is, but I really hope it isn't, for everyone's sake.