Why is it important for you to understand personalities in the workplace? Think of both, knowing your own personality, as well as knowing how to recognize other people's personalities.
It is important to know personalities because if you don't work well with other people you don't want to have a therapist job or job that surrounds you with other people. You have to know others personalities so maybe you don't say something wrong that would offend them or you don't want to put them in a situation that they cannot handle. My career is a nurse practitioner. My personality is good for this job because I like to be around other people and kids and like to help others.