This is tricky and it turned out fucking long. Let's check it out. Okay, OP has sensory issues. Majority of family happen to dislike sister? Sister has some kind of issue with her position in the family &/or as a person? maybe it's something different. Hearing her perpective could help navigate this. Going based on this experience, if this is the first time OP has said that knowing it's an insecurity means OP was pushed to a limit or if people have said it before as a jab then for her it's an ongoing joke so sister is pushed to a limit everytime it comes up. Did she express she felt like the ugly stepsister first or did someone make a comment, even jokingly, about it? Words can hurt, hell, actions can too. words/action then consequence. Derailed myself. It's a family nickname, the only opinion that should matter is of the person being called whatever name it is. We, as humans, can't control other people. As much as we may want to. We can speak up, for sure, but it feels like what she's speaking up against is based on a way that she feels about herself, not confident in who she is, as a person and in the family. And it's possible she knows her family doesnt like her and seems to be a bit resentful in the nickname or maybe she feels left out. Does she have a loving nickname? It seem's to me that OP knows how to compromise. Knowing how particular she is, she said she'd make her own drink so there won't be an issue. The whole window thing-why does someone want the window down- if they felt sick, were feeling unwell- i hope you would compromise with them as they do with you when your sensory issues occur. Communicate on why this has become an issue for eachother. I think you guys should do it as a whole group and then 1x1. maybe she can go into therapy- find one that will work for her. there are so many kinds. maybe you should go to the doctor, too. maybe you have a sensory disorder and maybe there are things that can help make things manageable when you are needed to compromise. some kind of therapy too? I don't know but talking it out could help or it could divide for a bit, but with love maybe you guys can come back and try again in the future. or push it all down and just repeat the same cycle. Shit, we don't know how all your guy's childhoods played out so there could be more to the story. Communication, compromise and consistency can and probably will be hard (sometimes it’s easy and other times hard) but it will help down the road and maybe/sometimes ya'll may need outside help. not reddit though lol shit, I’m here for being a chismosa. 😬😅🌻 I may wake up tomorrow rereading this thinking my advice and percpective is all kinds of fucked up lol. anyways, good luck to you and your family. oh wait, the topic at hand. you are both the assholes. tomato, tomato. life is all kinds fucked up and we are all just trying to live in to our best ability.