One time that I can think of -- I got an "I love you" virus from someone I knew, who would conceivably say that. But knew about the virus, deleted it.
Meanwhile, another staff member got it from the guy she had just broken up with, and opened it even though she knew better...
On the other hand, a friend was rather peeved at me that I hadn't show up for the party she invited me to. I swore up and down that I hadn't gotten anything, then remembered I'd gotten a "you're invited!" email with a large attachment right when I was getting warnings about the "My party" virus. So deleted that without opening. Oops.