How can I convince my younger sister to treat our mother with more consideration? I am 33 and she is 21 and she's always "walked all over" our mother, who has spoiled her because she's a single mum and often has little else to do. I'm always the one who picks up the pieces, the responsible one, and I know that comes with the age difference. However I thought she would grow up to at least have some consideration but she is still just as selfish as when she was a teenager: going to our mum for money when she knows mum has very little, insisting on favours even when she must surely know that it is awkward for mum. Our mother finds it almost impossible to say no to anyone, let alone us, but I can see her going without so that she can give my sister money to spend on frivolous things. She'll never clean up after herself and is perfectly happy to see mum doing all the cooking, washing up and cleaning without ever offering to help. I would always help, whether it was mum or anyone else, because I would see it as the polite or mannerly thing to do, but my sister will just eat the food, sit down with her feet up without ever offering to help and happily watch as me and our mother clean. This is just a small example. I have tried talking to her but she flies off the handle, often insulting me by saying I'm "jealous" because she's young and "has a life" while I'm "old" and "boring". Is there any reasoning with her? She doesn't feel at all guilty for asking our mother for money even when she struggles to pay the bills...what sort of person can be so selfish?