At the end of the Hunger Games (the movie) it shows Pres. Snow watching the screen and shows his face. He gets a really angry expression on his face and turns around and leaves. Is this just because he's pissed that there were two victors, or some other reason....?
Katniss' behavior threatened to commit suicide was considered as a revolt to domination of Capitol. The behavior itself and the potential effect to people pissed Snow.