Fascinatingly enough a bad golfer is consistent enough with his/her consistent mistakes and poor play, that it promotes even more bad golf and frustration.
Actually a bad golfer ignores or is unaware of what has to be the single most important aspect of the golf swing. This is the setup or positioning before the swing.
It does not matter how good your swing is and how much correct technique you have used. If you do not pay attention to your swing, you are a bad golfer and it will clearly show when you have hit the ball.
All great golfers are aware of how important the setup is and you can be sure that many bad golfers are not. If you setup correctly for a shot, chances are extremely high that you will hit a good shot. So important is your setup that even if you swing poorly in a good setup position, you are bound to at least hit a reasonable shot.
A good setup will enable you achieve a good posture and the sort of balance that will help you maintain balance and inevitably control throughout the shot.
The correct setup comes with correct training and even more important; exercising and conditioning of the muscles you use in your entire body for the swing. A bad golfer will more often than not be the sort of person who does not do golf-specific exercises aimed at improving their golf. The result is that they will not even be able to tell the difference between a good setup position and a bad one, simply because they will tend to feel uncomfortable in both.
It is amazing but true that all it takes to move you swiftly to the ranks of a good golfer from amongst the majority of bad golfers is a simple exercise routine, most of which you can even do from your office while you work.