Three siblings, how come the elder sister is the most obedient?

I have three siblings, and I am the middle one. Generally, this kind of situation is not popular at home, and in our era, it was very common to beat and scold children. But what is surprising is that since I was a child, I , my parents had never beaten me, and when I asked why, my father said it was because I was too obedient and could not find a reason to hit me. But my sister and brother were often beaten, and there are two scenes that left the most profound impression on me.

When my sister was in elementary school, her father once hung her up with a belt and beat her hard. The beating made her scream in misery, and her mother could not persuade her to stop until she was beaten. Dad only stopped when he was tired, which scared me silly. Later, when I became sensible, I found out that because my sister invested 50 cents from the family to buy snacks, my father was afraid that she would develop the habit of stealing, so he beat her like this. I hope I can remember it forever.

My younger brother was often beaten and scolded when he was a child. Once he made a mistake for unknown reasons, and his father put him in a vat filled with water, closed the lid, and refused to let him out for a day, nor did he give him anything to eat. The younger brother was so frightened that he cried.

To this day, we still occasionally talk about these things as jokes. Maybe this kind of thing was very common in my parents' generation. Beating and scolding were common, and I didn't think there was anything wrong with it. Although I didn't I have been beaten, but often denied, including when I am looking for a partner. My father often says, "You have average conditions, so what do you expect to find? Just find someone who is similar. In his eyes, his son is excellent, and both of them are good." As long as a daughter can find a partner, that's fine. This kind of concept makes me very low on self-confidence, and I also have very simple requirements when looking for a partner. Although I have healed a lot as I grow older, many of the choices and consequences that have been made cannot be changed.