In order to honor the 50th anniversary of psychologist Carl Jung's death, BBC recently discussed why modern people should thank this Swiss professional.

Jung is widely remembered for his work in developing a modern personality test, along with the many elements that are still included in some of these tools, according to the news outlet. For instance, the psychologist created the terms "introvert" and "extrovert." As individuals who have taken a personality test know, an introvert describes someone who prefers to be alone, while extroverts prefer to be in crowds.

According to the University of Oregon, extroversion is still considered one of the Big Five personality traits, along with agreeableness, conscientiousness, neuroticism and openness. Currently, there are many personality tests that are based off of these traits.

The psychologist also made other interesting analysis that influences modern personality tests. The media provider states that he created the theory that everyone has what he called a "shadow," or a dark side. This would explain why good citizens sometimes commit a crime or why even the calmest people can get angry over small things.