This is Gabe Watson in the waning minutes of the Arizona Cardinals-Dallas Cowboys Football game in Glendale, Arizona on Christmas Day, 2010. His team, the Cardinals, won the game 27-26. He's looking up - probably looking at the scoreboard or perhaps at a recent replay. In this context (but certainly not all), lip biting indicates vulnerability and anxiety. This expression is often present, but rarely "seen" in the context of business, law, medicine, politics, etc. When you see this, don't dismiss it. It should be a red flag - dig deeper.