Plenty goes into coaching: assembling a team, hiring the right assistants and game preparation, among other things.
But it is all for naught if a coach can't get the job done on gameday. Play-calling and in-game adjustments often determine the outcome of games.
Some coaches can't get it done. They wither in the spotlight. Overwhelmed by the moment, they lose track of time and forgo smarter strategy.
Here are the 20 worst in-game coaches in history.