I was discussing email privacy with a friend when I remembered something a classmate had said back in junior high.
Our algebra teacher, Mr. Powers, wanted all his students to keep a notebook. Occasionally he would ask that we hand these in for evaluation.
One guy who sat next to me back then joked that he was going to spice up his own notebook with comments along the lines of "Mr. Powers teaching a great class today!"
What's that got to do with email privacy?
Well, suppose you suspected that some manager at your workplace was reading your office email. Would it help to occasionally write things like "It's an honor to work for this company" or "My boss really dresses well"?
My guess is they skip over anything that's not at least R-rated.