It was a heated exchange like you don’t often see but will no doubt become commonplace over the next two years. Treasury Secretary Steve Mnuchin had testified for three hours and was anxious to leave to attend another meeting. From The Washington Post:

Their disagreement appeared to be over something innocuous — how long Mnuchin would continue to testify at a hearing — but Waters refused to budge and Mnuchin became furious when he wasn’t dismissed more than three hours after the hearing began.”

Most of the questions were over Donald Trump’s tax returns and when the Treasury Secretary would provide them as required by law.