DH just announced his hill to die on.
It was two years ago when we did T-day at his dad's. We were invited about 2 weeks beforehand. We drove 3 hours for the lunch and would drive back home in the afternoon. FIL and his wife were aware of why we needed to be home.
It ended up being basically all my FIL's wife's family (DH doesn't call her StepMom for various reasons so I will call her FILW). It was going to be FILW's two married children and their families, her mother, and 4 other friends of her family.
And while we were invited, we weren't exactly welcomed. From the seating arrangements -I was basically on the corner with barely room to move- to very few people who would talk to us, it wasn't a nice visit. About the only people who would acknowledge us was FIL and FILW's 5 year old granddaughter. That was it.
Dinner was postponed about half hour since FILW's son was late. No real reason was ever given. After lunch, they hung out and talked around us. So about an hour and a half of no-one really talking to DH and me being the unoffical babysitter of the little granddaughter, we looked at the clock and said that we needed to get on the road. (about 3, which is when we said that we would be going) Suddenly, we were the center of attention. We just couldn't go. They hadn't served pie yet. Why would we be leaving so soon?
Pie is served, and oddly, the four friends of the family also had to leave.
We are whined at that we should stay longer. I remind them that we had left the dog for the day and needed to get back to her. I was told that dog would be fine.

I was the one who then pushed us along to our car (I am sure that I was considered quite rude for not wanting to stay longer)
All the way home DH was fuming. (Not at leaving, but the fact that it was very uncomfortable.)
*Why, yes, there is some additional background of weirdness with FIL and his wife. But that would take too long.