Apparently a lot of people were asking Roy Hibbert why he looked mad during the Pacers' win over the Bobcats. Or he just felt like telling the world. Either way, this is a perfectly valid reason to look mad:
I looked angry during the game its cause I used flexall/Bengay on my knees under my black tights. Somehow it got on my balls. Burned so bad— Roy Hibbert (@Hoya2aPacer) December 14, 2013
This was a popular summer camp prank back in the day, and I can confirm it makes for an angry face. Still not sure how Bengay works upward from knees to crotch, but I will not ask further questions. I fear a vividly descriptive answer.