The Japanese concept of "Kaizen" or "Change for the Better" is at the heart of the martial arts journey. This concept catapulted Japanese industry into some of the most effective companies in the world. This concept of "Kaizen" has been adopted by pretty much every successful company worldwide. Companies world-wide have sent representatives to Japan just to study their methods on ensuring maximum quality with maximum profits. Anyone that has studied business management has been taught this extensively with whole college courses dedicated just to this concept and the techniques to implement it.
This concept should continually be applied to your martial arts journey. The martial artist should keep an attitude of changing for the better. No practitioner of any art, martial or other ever reaches perfection. Perfection is more of a journey, and not meant to ever be reached. Perfection and beauty is found in the struggle and never ending quest to reach it. It is this struggle in which you learn more about yourself. Every time I have ever taken a black belt examination, it has taught me something significant about myself. For example, my very first black belt exam made me face the unfortunate truth that I had been guilty of self-sabotaging my successes. I discovered that I never truly believed that I could succeed at anything worthwhile. This lack of belief in myself caused me to subconsciously sabotage many things in my life. Sometimes what we discover about ourselves is unpleasant, but necessary for our personal growth.
In your training, do not be discouraged or insulted by your instructor's correction. Learn to be receptive to it, as a good instructor is constantly trying to take you to a higher level of refinement. Constantly strive toward the refinement of your techniques and strategies. If you can get a full understanding of this, you will find that you will not get discouraged as easily in your training. Remember, discouragement and broken egos are the two biggest reasons people quit their martial arts journey. Our own feelings can easily become our biggest obstacle in life.
A "Kaizen" mindset will help keep you open-minded and receptive to correction. Don't get so focused on the end-goal that you are not aware of the little victories we have each day. No one ever became a black belt overnight. In fact, when we achieve that goal, we often find that it was just the start of the next journey toward perfection.