Rather than a relaxed feeling be 'at ease' on the golf course. Positive thinking on the course is an important ingredient in the recipe for good rounds and negative thoughts are pure poison for the golfer. You need to believe with all your heart that the shot you are about to hit will be a good one. For this you'll need complete confidence.
All the above might sound a wee bit of a challenge to a player who doesn't break 90 but the difference is between confidence and optimism. Confidence is when you have hit a particular shot many times in the past with success therefore, you know you are capable of doing it again. Every golfer has hit a particular shot with success many times, so the ability is there. Optimism would be if you had never hit a shot you're facing successfully in your life, and you're hoping this will be the first time. A golfer must learn to turn off all these voices, as a good golf swing happens right now, not in the past or in the future.
Out of Bounds: The less you respond to rude, critical, untalented and argumentative golfers… the more peaceful your life becomes at the 19th.