TV characters usually leave an impact on audiences because they build a sense of familiarity and reliability. The more viewers watch these characters, the more they come to recognize their ways of thinking and behaving. On the other hand, there are some characters whose only consistency is being inconsistent. Their unpredictable nature is often a driving force of their show's plot, and it can be extremely entertaining to watch.
Source：https://www.cbr.com/unpredictable-tv-characters/
