"I hope to God I never have a kid like you."
/When I was little, I had a lot of emotional problems and developed PTSD. Because of my anxiety disorder, I was very particular about things that literally didn't matter at all.
One year on Christmas Eve when I was 6, I decided that the ginger bread house I had made with my uncle and cousin wasn't right, so I wanted to do it over again. This upset my uncle because we had spent hours on it and now I was persistent that we had to start over.
After arguing with him for a while, I finally stormed off in a tantrum about the situation and went to the living room to cry and vent. A few minutes later he came over to me, and I hoped he would comfort me. Instead, he proceeded to tell me words that would stick with me forever.
He said, "You acted like a brat!" He sighed and continued with, "and I hope to God I never have a kid like you."
He was about 30 at the time and had his first child 5 years later. While he's never apologized to me for the incident, his son has problems of his own, and I like to think that he now regrets saying that to me all those years ago.
Regardless, to this day we don't have much of a relationship, and I generally avoid spending Christmas with my extended family to avoid incidents like this.