Low-functioning 4s are incapable of accepting their own mistakes when they make a negative impact on others. Which is actually rather often to be quite honest. An inability to accept faults is something that needs to be consciously worked on because it helps a person grow and become a better person. Much like how an 8 must work on not dominating everyone and everything in their environment, and submit when it is necessary instead of mindlessly trying to lord over everyone, 4s must learn to accept uncomfortable aspects to their type which is a tendency to see themselves in a way that may not be accurate with reality.