The worst experience I ever remember was the one day when I was about 16 and called my mother a 'bitch' - my father didn't use a belt that time. I remember when he found out he called me out of my room and asked me "What did you call my wife?" - growing up my father whenever talking to me or any of the kids had always referred to my mother by saying "your mother". I got punched in the mouth and I will never forget it. More importantly, I learned my lesson the hard way.
How come all those years of discipline with a belt resulted in a 16 year old who was calling his mother a “bitch”? Sounds like the belt approach didn’t work too well.
Your dad sounds like a fine man!