"You're right, Fred, I don't slink off because of a disagreement. I do it because of a lifetime of disagreements culminating in the one where I am finally informed of just what my own family thinks about me." Percy shook his head, amused in a bitter way.
"It astounds me, your shock. All of you. Even dad. How much do you expect a person to take, Fred? How much relentless bullying is a person entitled to before they're allowed to walk away?" He faced Fred, trying to stay level and simple. "I don't have a single warm memory of the Burrow that doesn't end in humiliation. Not one. No single Christmas, no birthday, nothing. Every single one ends in 'shut up, Percy' and 'go away, Weatherby'."
He straightened, regarding his brother with some pride. "I know exactly what went on at that wedding. I know more about Bill's actions that day than Bill probably remembers. You can say what you like about my job, but I know what goes on in the world." His expression sharpened, becoming a dare. "When you were all coming together, what would have happened if I had shown up? Bill would have had to recover with the sounds of fighting and arguments in the background. Our parents would have had to split their attention between the people who needed it and their unpleasant returned prodigal. You know my being there would have made everything worse. You're too smart not to know that. So stop accusing me of staying away when you should be thanking me for it."