Put it at the end of a failed explanation, after No No Wait Wait sets up the confusion, then follow it with Damn to underline the verdict and close the scene without adding another reaction.
Über diesen Sound
This is a 1.7-second German voice clip built around the phrase Genau Dumm, spoken as a blunt, deadpan dismissal with no extra words to soften it. It gives a dry, mocking feeling, like catching someone in an obvious mistake and answering with a single flat verdict. The brevity makes the judgment land harder, leaving the listener with a sharp, amused sting.