For which no one blames either of them. The topics, according to Kerry, were Ukraine (we would like Russia to stop participating in the civil war there), Syria (we would like Russia to stop participating in the civil war there), and Iran, an ally of Russia with whom Kerry and President Obama are desperate to negotiate a diplomatic treaty. Grim topics! Grim facial expressions.
Kerry may also have been angry that (1) Lavrov had a better suit-tie combo or (2) that the stars on the American flag were so freaking big. But he's a professional, so we'll assume he was just mad about the war stuff.