I too have a sister whose favorite line is "How come you're so different and we were raised the same?"
Once I explained to her how we weren't raised the same, although in the same house with the same parents, she realized I was right! That was a first for me being the youngest in a family of four. My sister is 5 years older than me.
I was born in 1952 and my mother stayed at home and looked after us until my father died when I was 13. He had been very ill for 7 years or from the time I was 6. My sister grew up in a home with a mother and father, both parents were actively involved in her upbringing, education, life lessons and discipline. My sis was 18 when my dad died.
I was brought up with a father who was too ill (he died of emphysema) to be involved, a mother who was looking after a husband who was dying and went back to work full time the year I turned 13.
From the time I was 13, I had basically no parental supervision....my mother was either gone to work when I woke up or at work when I came home from school. I was on my own to get my own meals and really do whatever I wanted. My sister and brothers were already working and as older siblings will do, really paid no attention to me at all. All of them had moved out of the house by time I was 15.
So, we really didn't have the same parents or upbringing.
My sis and I have a great relationship now but for many years it was difficult (for me) being criticized for my decisions and actions.
By the way, I guess my mother was influential enough as I just recently retired from 38 years with the same company and had many sucesses in my career....not so much with the husbands.
Before you beat yourself up emotionally (which I did for many years) or sever your relationship with your sister, think about how you were both raised and it might be helpful to point out the differences. Or you can just ignore the b**ch!