In order for the ego to deal with pain, it can develop certain mechanisms in order to make it more manageable. A defense mechanism reduces or attempts to reduce psychological pain.
Personality development is a phrase that also means personal development. Personal development is a wide subject but in summary it is all types of ways that you improve this can be spirtuality or...
This would be something that changes per individual. If we were to base the answer off of the Personality Types theorized by Carl Jung, then expounded by Briggs/Myers, we would come to a conclusion...