Alright, so my sister told me that if her roommate wasn't making dinner, we could do a joint meal (like we've done multiple times) since my SO and I dont have much food atm. After that, we got into a small argument and I walked away before it got really bad. So a few minutes later, I head back upstairs to ask if we're able to do the joint meal and she said no as SHE was the one cooking.

Okay, its one thing to be upset about an argument and not wanna be around the person for a bit. But its completely uncalled for to lie to their face about something you had already said was okay.

Idk maybe I'm overreacting, but she does shit like this all the time and I cant freaking take it anymore.

Like that is one of the rudest things you can do. Ugh.