The most common cause of mortification in your dream is rejection from someone we love and care about- maybe a friend or family member, or even our spouse or significant other.
Mortification in dreams can suggest that you have been doing something distasteful on the conscious level. Sleep enrages because it is an escape for guilty thoughts that happen late at night when people are more vulnerable and likely to experiment with unfamiliar behavior without questioning it further.
People who experience dreams where they feel shame may want to examine feelings related to morality and values in their daily life more closely and remedy the issues before they fall asleep again in the future.