Rule of cool

In short, the Rule of Cool states “The limit of the Willing Suspension Of Disbelief for a given element is directly proportional to its degree of coolness. Stated another way, all but the most pedantic of viewers will forgive liberties with reality so long as the result is wicked sweet and/or awesome.

In an RPG, the Rule of Cool means giving your players the chance to perform ridiculous stunts or bend the rules a little bit in the sake of an awesome scene.