I was 'smacked' when I was a child.
At age 6 I was hit round the head with a hairbrush when I was fidgeting having my hair tied up.
At age 8 I had my trousers and underwear pulled down in front of family and had my arse slapped for answering back.
At age 11 I had my face slapped for hurting my sister. It was so hard that it left a swollen hand print.
At age 15 I was pushed into a wall by my throat for defending my younger sisters.
At age 16 I watched my dad and sister head to head arguing and she told him his breath stank and he head-butted her.
My mum threw a dinner plate at my sisters head once. I watched my mum grab my sister by her hair and push her face into the floor.
My sister was hit so hard around her head that her earring got lodged into her ear.
It might sound extreme, but things can escalate quickly. There is a very fine line between discipline and abuse and it is easy for those lines to get blurred.
At one point the police were called by neighbours and the police did precisely jack shit. We ended up having a meeting with family mediation. They denied they were violent. End of meeting.
They hit us because they were angry, because they were frustrated or because they just didn't know what else to do. It started as a slap on the bum as toddlers and the force and frequency increased as they lost control, as we got older. I don't consider that we had an abusive childhood,we were loved and I honestly believe my parents did what they thought was best, but it was certainly filled with bullying and violence. I was scared of them until I realised the worst they could do was whack me. I toughened up.
Even now, (we have an ok relationship) but they laugh when I suggest they were violent. They insist that we were mouthy teenagers and they just 'smacked' us. They used to say, "wait 'til you have kids and you'll understand."
I have 4 kids and I've never felt the need to use physical or verbal abuse to convince them to behave in an acceptable way. I would not assault my DH or any other adult or child, so I treat my DC with the same respect.