Or it won’t happen when you’re watching, because then they’re thinking about what they’re doing and they don’t make the same unconscious mistake they did that brought up the error message. Then they get mad that “it never happens when you’re around. Why do you have to see the problem anyway? I described it to you.”
Bud Clark for the win.
https://upload.wikimedia.org/wikipedia/en/7/78/Expose_Yourself_to_Art.jpeg