Actually, I think there is a Rule of Goofy, and it goes something like this:
The ability of an element to shatter the Suspension of Disbelief is directly proportional to how goofy it is. Reality is no excuse for fiction. If the audience finds something so goofy that they are thrown out of the moment in order to analyze or scoff at it, it doesn’t matter how realistic it actually is or how well-documented it is that such things occur either in the real world or in the genre. Presenting evidence might get them to move past it, but the damage is done and the momentum is lost.
For RPGs one might add that the element might be a result coughed out by the game system that, while 100% accurate to the rules, is goofy in context.
While Dr. Checkmate is correct that one man’s cool is another man’s goofy, that doesn’t mean that the rules can’t be usefully applied, only that you have to know your audience.