Take THAT, Ma!
Most of the time when I get an email meant for someone else, it's because that person doesn't know their own email address. In this case, it's because the sender didn't know his mother's email address. And I know he doesn't know it, because he guessed at 5 variations and sent this to all of us.
I can't decide what's worse, that Joe doesn't know how to contact his mother, or this insanely passive-aggressive message.