Bullying e-mails

I just got a note from an old friend reading, in part, 'Of all the friends I ever met / You're the one I'll never forget.' Me and the 40 other people she mailed it to. It had that kinda threatening tone, like if you don't do what I want with this we're not really friends. Whyever do people send notes like that? Another correspondent sends notes with little made-up inspirational stories, again with an added tone of 'Well, what are you gonna do with this?' Delete it, as I did the 'friends' note. Friends don't coerce friends.