Seems like vile sisters aren't so uncommon. Mine's eight years older than me (she's 54, I'm 46) and thinks I'm an airhead.
You see, although I have two grown up kids and a very happy, 27-year marriage, I don't behave myself. I go out rocking it up with bands, hitching rides on motorbikes and flirting with blokes. I only work part-time and gave up a full time job so that I could spend time at home writing books, even though I'll probably never be properly published. Last year I swanned off to the states on my own to visit my beloved cousin.
Sis, however, wouldn't do anything like that, so therefore I'm doing wrong, in her eyes. She is a very straight-laced, sour-faced old goat and lives only to earn (and keep) money. She's currently working on the ensnarement of a third husband. Fortunately she has no kids.
This, orange-gnome, is where I draw my comfort. It took that beloved cousin to tell me (he dislikes her as much as I do, so I know it's not just me) that when we're all old and grey, he and I will have our kids and a whole bunch of people who want to be our friends because we actually have the time of day for people other than ourselves and aren't old miseries 99% of the time. This is something she won't have. She will, he says, die a very miserable, lonely old lady.