There are well over 200 muscles at work when one hits a golf ball. If all those muscles are to do what is intended of them, they must be in harmony with one another so the swing can be executed smoothly.
The only thing that keeps the golfing machine (swing) running smoothly is perfect balance. Any imbalance, no matter how slight, causes muscles to deal with these imbalances rather than take part in the smooth execution of the swing.
For instance, if a player bends his knees too much at address, the legs end up supporting the whole upper body and therefore will not allow the weight to shift as it should. In most cases the rear leg straightens in the backswing and the forward leg straightens in the forward swing creating a reverse weight shift; a shinning example of one's reflexes at work.
A well-balanced golfer tends to move smoothly. Fred Couples, Ernie Els, Steve Elkington and Sam Snead all come to mind. Golf swings unencumbered by compensations for imbalance create great rhythm, timing and club head speed. That's why these players can hit it so far with very little apparent effort.
Balance can be a very illusive thing; coming and going from day to day, nine to nine, hole to hole and even shot to shot. There are two types of balance, static and dynamic. Static balance is what you have when standing still; while dynamic balance is balance in motion. Because the swing begins from a relatively static state, one can be statically balanced and not be balanced dynamically. Which means that once the swing gets underway, reflexes take over and the whole motion is compromised as one struggles to maintain balance.
Dynamic balance is achieved by putting yourself in a certain position which I like to call a Profile as opposed to Set-up. Just as each player differs in stature and flexibility, this position may differ as well. But let me warn you, too much of a variation from this position will cause your reflexes to take over as you struggle with balance to hit the ball.
"No matter how bad you are playing, it is always possible to play worse."
"When your shot has to carry over a water hazard, you can either hit one more club or two more balls."
"Counting on your opponent to inform you when he breaks a rule is like expecting him to make fun of his own haircut."
"Nonchalant putts count the same as chalant putts."
"It's not a gimme if you're still away."