e-mail pet peeve

I don't mind when people forward things on to me. Yeah, we all have that friend who forwards everything they get to every name in their address book, including to the person who sent it. What really gets me, though, is when they don't forward from the original message and you have to open about 12 e-mail windows to get to the actual desired message. Does this not annoy everyone else? And if so, why do people continue to do it?