When I was in high school, I took Advanced Placement English in my senior year.
(A note for those not familiar with the American education system as it existed in my time: high schools often provide “Advanced Placement” courses for students who are capable — at least in theory — of college-level work. These courses end with concentrated standardized examinations to determine how well the students understand the subject material. Some colleges and universities will allow students who do well in these tests to receive course credit, or to skip basic courses in the tested subject areas. Common subjects for AP classes include Calculus, Physics, Chemistry, and English.)
Towards the end of the year, when the examination was drawing near, the teacher spent a day of class time giving us some examples of what we might expect on the test. For the most part, everyone in class did well, and we moved quickly. We pulled apart poems, explained symbols, traced references… and then we hit a blank wall.
The teacher had given us a brief work, dating from (as I recall) sometime around 1900, or at least written in a style which could pass for the work of that time. I have long since forgotten the precise authorship and title, but the topic was the (disgraceful) history and behavior of an aristocratic family. Nobody in the class could make anything of it. The teacher gave us an embarrassingly long time to offer an explanation of the purpose of the essay, and then began the time-honored process of asking leading questions.
Finally, someone in the class stuttered out that the piece didn’t seem to make sense, and suggested that it was perhaps intended to be humorous. Upon confirmation from the teacher, the dam broke. Suddenly, everyone in the class was falling all over themselves to list the jokes.
Our teacher was somewhat disappointed that we did not immediately see the humor in the piece, but, he admitted, humor was something with which AP English students always have trouble.