I share a bathroom with my 21 year old younger, sister and i swear to God, she does not clean at all. She doesn't "take one for the team" so to speak. There could be a dead animal in the corner from who knows and she would rather let it be than clean it up. I'm not a messy, messy person but when it gets messy (from the both of us), I clean everything; not "selected" cleaning. I've never seen her clean the bathroom at all. The plug in the tub could be full - I'll ask her and she'll ask, "oh I don't know". There's leftover dirt and sud in the tub and she'd leave it there. The toilet paper can run out and it's still there hanging without any paper. The makeup remover towelettes would run out and she'd leave the packet still there -common sense, you're the last person who used it, throw it away! I've called my parents about the situation and they're (of course) easy on her (youngest) and defend her and give excuses to this behavior. It's batsh8t crazy, bullsh8t. Grow up.
I've been blunt with her in the past - she makes the "i'm right" argument and recently in past years, when I do show my anger (which has been hard since I've always been the protective older sister but now that's changing), she does listen...but makes it seem like she did it on her way. I don't know it I should use that same sarcasm (she has) and put on her and say, "look. when this runs out. We put it in here. This is called the trash.".... please help....