Saying you are going to do something simply because of who you are. The highest level of self-confidence and overemphasis of your abilities.
Hernandez himself when he makes a move on Elaine in a 92 episode of Seinfeld simply because he was Keith Hernandez. Michael Jordan making 3's in Game 1 of the 1992 Finals and shrugging to the crowd. Matt Leinart slinging the ball long on 4th down against Notre Dame. An athlete especially has an "I'm Keith Hernandez" moment when he decides to do whatever he wants because of his own name and identity. Frequently used by ESPN writer Bill Simmons