Cleanliness

I was talking to someone who said in her house (she shares it with 3 other people) about how no one absolutely cleans anything up in the kitchen and just leaves the dirty dishes and pots there to stink up the place...I really don't know how people live under these conditions, and they can just take it....I'm not a super-clean freak by any chance like my dad's friend is (that guy will pick up a leaf as soon as it falls to the ground outside), but I want a clean house that smells nice and is truly a home, not a cave! My sister makes such a mess in the bathroom whenever she leaves for school...towels and clothes all over, makeup on the floor..and the worst thing is that she doesn't care at all, she just continues doing this EVERY single morning!! I pick up after her if I come home and find that its still like that (since I have no time in the morning to clean all that), but she's going to run an unclean house or dorm or w/e in the future not knowing these proper manners and basic skills....I don't know what else to do, as I've told and yelled at her many tims, but she still contines with the same crap! A note to any future parents: Be a good role-model for your children, and make sure they understand the importance of being clean!