I'd just stepped out of the shower when MIL and FIL (staying with us for family Christmas) started to have an animated conversation outside the bathroom door. The gist was that they were pleased to be heading home because I'd made them feel unwelcome and unwanted and ruined their Christmas.
I could have opened the door at that point, but decided against fanning the flames and waited in the bathroom till I heard them go downstairs.
I didn't want Christmas to end with an argument. And I can't see any benefit in raising this with them when we next talk.
WWYD? Let sleeping dogs lie or ask for an explanation?