Those who know the Guy in real life (or at least, did till a couple of years ago - I believe he's sobered up since he found a ready target to unleash all his wit on right at home) have a healthy fear of his witticisms. It is rare to be able to say something that he finds himself unable to counter.
We were on our way home when he took a less familiar turn. "Why are we going this way?" I asked politely, once the turn had been safely navigated.
"Sorry, I forgot."
"Oh. I thought you'd decided to take this route for some reason. That's why I asked you politely instead of just shouting 'Turn left!' as I usually do."
"Yeah, that's what you usually do," he said peevishly. "You don't imagine I may have actually thought it out and might be doing it deliberately."
"And the only time I do assume so, you prove me wrong," I sighed, then burst into maniacal laughter as the Guy struggled to find words.