George was not being helpful, in Percy's opinion. All he'd wanted was for his brother to simply admit he had done something to Percy's bedsheets that had resulted in these marks on himself and Daphne - and hopefully help him find a cure - but no, George kept insisting that he had absolutely nothing to do with it, even going so far as to wish he had since it had gotten such a rise out of Percy.
It was almost enough to have Percy believe his words. Almost. Unfortunately for George, Percy had spent so many years as a victim of the twins' practical jokes that he no longer believed denials, as they were rarely true.
In his anger and frustration, he accidentally knocked over a display of Skivving Snackboxes, almost landing the table against a nearby display of Whiz-bangs.