This setting allows you to control how patient your coach is with your goalies before he pulls them out of the game. If you have your patience set to "Only pull his as an absolute last resort", it's a pretty safe bet that the starting goalie will never be taken out of a game -- no matter how many goals he allows. If you set it to "Pull him after his first mistake," the goalie is yanked quickly if he starts allowing goals. The situation does vary based on the time of the game and how quickly the goals are scored against him.