Everyday, I see people that do not know how to deal with other people's opinions. They see it as criticism or being put down. These folks have never learned to separate coaching, criticism, and negative comments. Everything is take personally. They over react. It makes them difficult to deal with and difficult to have as an employee.
As a generalization, this trait is dominant in people who are only children. Perhaps it is because they didn't have to share and get along with others, and there fore did not develop a "thicker skin" along the way. And yes, there are exceptions. Remember, this is a generalization.
It takes a lot of time, kindness, trust, and willingness to change to alter the behavior. Once the change is made, the individual seems to go on to achieve goals and to grow in abundance.