One of the most frustrating problems for a golfer to experience is the feeling of repeating a bad shot over and over, with little or no understanding of the faults and, therefore, of the relevant correction.
If a golfer can learn the skills of self diagnosis, it can save an awful lot of frustration and an awful lot of golf shots for a player. The ability to understand one's fault during a round of golf and therefore set about making the relevant corrections mid round can really separate the good players from the less experienced high handicappers.
Next time you are at the driving range or taking a lesson, try to approach the session with an open mind. One that is willing to really get to grips with understanding your own swing, and not only the good bits, but also the bad bits.
Trying to understand how each and every part of your swing is interconnected and responsible for producing different results both good and bad. If you can then appreciate how you are able to control your swing, you should be able to self diagnose when you make a mistake and start to implement the relevant corrections so that you don't keep repeating the same frustrating, damaging bad shots throughout your round of golf.
Trying to self diagnose and self correct on the golf course can be dangerous for some golfers as they either diagnose the wrong issue or implement an over correction, for example, turning a slice into a hook or a thin into a fat.
However, with practice and subtle alterations to your movements you should be able to self diagnose, self correct, and ultimately feel that you have control over your swing and your golf ball, without the need to rush back to the practice ground or your coach to find out what you did wrong.