Showing good Sportsmanship means to play by the rules and be nice to your opponent, even if you are losing.  Other ways to show Sportsmanship in golf include playing fast enough to keep up with the group in front of you, and shaking hands at the end of the round.  Unlike some other sports where players often get angry and throw temper-tantrums when losing, you will rarely see this happen to a Professional Golfer because it's so important to keep a calm state of mind and uphold the integrity of the game.