The great part about Japan is that the inane social system they have set up here forbids them from challenging your assertions and have to accept all your lies at face value.
Me: “Oh yes, it seems I forgot to stamp my hanko for last Friday. I’ll do it now.”
(Sucking through his teeth) JTE: “Ah yes, but, Kyoto-sensei does not, ah, remember you on Friday…”
Me: “Hmm…well he must be mistaken. I was definitely here…perhaps he didn’t see me because I might have been upstairs.”
(More teeth sucking)… (then he leaves)