My dad NEVER raised his voice at me, only spanked me once ever and I was terrified of upsetting him. My mom on the other hand yelled, screamed and beat my ass but I'd push her buttons just because I could.
I agree. My kids can get a certain look from their dad and they straighten up and he has never laid a hand on them yet I can yell, scream, threaten their life and they walk all over me. He was always the disciplinarian and now that we are no longer together taking control full time has never been harder. However, they do learn from our example. Good luck!