Why do some people have a pattern of getting bullied everywhere they go?

Including me I have noticed this since I was very little, you could say it’s a teenage thing that kids are assholes and once you’re an adult people are civil but this isn’t my experience at all, I think to some extend people just know you’re weak and you won’t defend yourself so sooner or later they bully you and use you as a punching bag. I have seen this happen to myself and other people and I don’t understand why it keeps happening, why am I even getting attacked in the first place unlike other people who have some normal adjacent social standing just for existing? It’s to the point I feel like I deserve this