Sis is being a SS about Father's Day. She doesn't want to do Saturday nights for dinner, it has to be Sunday. But between my family and Dad, we're in church all day. And Dad has a standing family dinner with his girlfriend, her kids, and us kids. Sis also doesn't want to do dinner with GF's kids.
Dad really wants this dinner to happen, he's asked me to organize it so we can go through old family photos. I finally got everyone to agree, we set a time and agreed on Father's Day, which took about a month and a half of negotiation to settle on.
Today Sis called wanting to change the plan from dinner at my house (which was originally dinner at Dad's, but was changed because one of GF's sons is staying with Dad til he finds a place). Now Sis wants to go out to eat. Nope, not going to happen. We try to avoid going out on Sundays, as does Dad. I told Sis that won't work, but I can make anything, what did she want? All she wants is to go to a restaurant. I told her I'm not going to a restaurant on Sunday, but if she wants to organize another dinner, I'd be happy to come. She got upset and snippy with me, and asked what's wrong with Sunday. For the third time I told her that we don't go out on Sundays. Sis flew off the handle, called it "BS" and said that she knows we don't just stay at home every Sunday. That's stupid. I told her we keep the Sabbath, and she said "well, that doesn't matter to me." Told her again that she's welcome to come over Sunday at x o'clock, and if she wants to make plans for another day, let me know and I'll be there if I can.
Sis hung up on me. I think she won't be there on Sunday. It's fine if she doesn't feel comfortable with GF and her kids, Sis has to come to terms with Dad's new family members on her own terms. And if this was a one off, I would be much more sympathetic. But it's her nature to throw tantrums and demand that everyone conforms to whatever she wants whenever she wants it.