The example that makes sense immediately still needs to survive an unfamiliar case.

An example that lands instantly is doing something slightly suspicious, since it fits what the listener already believes, which is why it feels so clear. Understanding that arrives without friction has usually not been tested against anything. The real question is whether the idea holds when the case is odd, when the details refuse to line up, when nobody has arranged the facts to be illustrative. Clarity and correctness are separate properties.

After something makes immediate sense, look for the awkward instance rather than a second confirming one. If the idea survives there you have learned something, and if it does not, you learned it early.