The stem on the cherry
I have one guy that forwards me every conservative propaganda e-mail that touches his inbox. Sometimes in the past when they were blatent lies I'd reply with a snopes link, but usually its too much bother.
I noticed after a while some e-mails had that header "checked by snopes" which really made me curious as I highly doubted it, so I'd check snopes and sure enough it was nothing of the kind.
More time passed, and I noticed sometimes he'd write that he hadn't had time to check it with snopes, but "you can't always trust Snopes!"
I'd set up a filter for his e-mails, but very rarely he sends something personal which I'm glad to get.