If you think that someone who is offended at a joke has no sense of humor, I invite you to watch this scene from the movie The Lives of Others. The setting is East Germany, Stasi headquarters. Please watch before you read further.
You probably all agree that this prank was cruel. Why? Because the perpetrator is of a higher rank and the joke involves a threat to the person’s career. Notice how the lower-rank member cannot shake off the anxiety even after he discovers that this was a mere joke.
Now let’s see how this translates into an April’s Fools prank. Suppose you are in a position of authority over someone: teacher, landlord, employer, military officer, etc. You decide to make a prank on your subject(s). Add to that a threat to the person’s career or livelihood, and you become a sadist, not a comedian. My son’s teacher threatened his education through an April’s Fools prank. Although I learned within minutes that it was a joke, my heart rate climbed and stayed there for over 30 minutes. I had a pain in my chest for even longer.
Be mindful of how your jokes could affect people. If you are in a position of authority, be extra careful. If in doubt, don’t make a prank. Causing people distress is not funny.
As a side note, you might want to watch the whole movie to gain interesting insight into phone surveillance and other subjects that still plague our modern world.