Well, a decade or two later and I am pleased to say yes it has improved and yes we do now get along. And not just in a "lets tolerate each other for the sake of our parents" or "you've only got one family you have to make the most of it" sort of way. No. More in an unconditional love, support and loyalty way of three best friends.
It's hard to pinpoint exactly when and why this change occurred. Certainly, leaving home helped. As did a growing maturity and awareness in each of us - awareness of how great our childhood really was, and how lucky we were to have a fundamentally happy home.
In the hustle and bustle of our twenties - with gap year travels, new jobs, university, boyfriend sagas etc - I think we all relished the comfort and security of coming home for a few days at Christmas or on birthdays. I think we all appreciated home comforts more and more - and the easy familiarity of just being ourselves.
A few years on, and this is now the third successive year that we have all gone on holiday together: the first time, fretting over our fledgling baby bumps, then last year cooing over two 7 month old babies, and now laughing along with two hilarious toddler cousins who adore playing with each other and are a constant source of joy.
While my little family of the husband and the boy are the very centre of my life - I will always need my sisters. They have come to my rescue on many an occasion, not least when I was recovering from childbirth and mental illness. When friends and colleagues were few and far between, my family stepped into the breach - faced the psychosis, supported my husband, loved my baby, mopped my brow.