Well, it happened to me. After swearing I would never do it. And for something minor too.
We were bringing groceries home and I was carrying a pretty heavy bag on my shoulder. My four year old kept wanting to be carried - he was just goofing around. But I kept telling him I couldn't and that we could hold hands instead, but he kept grabbing onto me and stopping me from moving. I told him I was getting angry, the bag was heavy and he needed to stop it and just hold my hand. But no.
I shouted at him. I was so loud. I never thought I'd do it. He cried and didn't want to move. My spouse had to come get him. The little guy was shaking for the longest time and after a couple of hours we were both talking again. I apologised but damn. I don't know what came over me. It was just so sudden – and I used to be the most patient guy ('used' to be, before kids).
Anyway. This is not a big thing but just needed a place to say it.