“The ability to regulate emotions is an essential component of emotional maturity and emotional intelligence. “When a person allows emotions such as anger, sadness, guilt, and fear to impair their ability to think clearly, it indicates a lack of control and understanding of their feelings,” explains Antoinette Bonafede Shine, a licensed clinical social worker and expert in personality disorders. This means they probably won’t be able to communicate their feelings productively to you: “If a person’s state of mind depends on their mood, their feelings control them rather than the other way around,” says Bonafede Shine. This can be brutal to deal with: Not only will you always be unsure of what might trigger the next impulsive reaction, but you’ll always be waiting for the other shoe to drop.”