Serious expressions
Obviously some people have trouble telling the difference between a serious statement and a tongue in cheek one.
Years ago, when I was doing a second job, which, by its nature, was a stress free job, at review time my supervisor said "I can never tell when you are being serious and when you are not." I thought about it and went back to him and said "I don't know either." It appears I use irony bordering on cynicism a lot as a way of, hopefully, making people think.