Parents.

Apparently, my parents once again have one of their little "misunderstandings" (read: fights). I think I know why, too.
In September, they and mum's brother and sister are flying to the US to take a month-long road trip in a caravan. Dad has been planning this since about this time last year. Which is understandable, because the sooner you book, the lower are the prices, unless you book last minute, which is not something you want to do on a trip like this.

Anyway, he's not only been planning. There is already a multipaged booklet about the trip, with maps, aerial pictures off of Google Maps, and detailed time schedules. And mum is more of a spontaneous type - like me, when she goes somewhere and likes it there, why not stay a while longer? While dad's more of a "the journey is the reward"-kind of thinking.
Furthermore, he can be a bit single-minded sometimes, so for the past year, we've been hearing all about the US trip over and over again. And knowing mum, she's been swallowing her annoyance until it got too much and it broke loose, and things escalated from then on until someone said something like, "I'm not going", and / or dad felt unappreciated, and loud words are followed by long silences.

I find this much easier to deal with from miles away, I'm rolling my eyes and thinking, "oh no not again", but I sure hope they get this over with by next week Friday.