相席（あいせき,） means “sharing a table with someone you don’t know (e.g. at a restaurant)” (Takoboto).
What other fun words have you all encountered that just don’t translate well to English or require a short explanation?
I’d like to make a sentence that’s very long in translation, and/or read a silly sentence like that.
Maybe ご多忙中 (ごたぼうちゅう) is a good example? Something like “Excuse me for interrupting you when you are so busy”.
Edit: 盥回し (たらいまわし) - handing off a problem to someone else to evade responsibility