That's according to the University of Innsbruck in Austria.
More than 1,000 adults were surveyed about their taste preferences with foods and drinks that are bitter. To get answers, the adults in the study took four different personality tests that examined traits like narcissism, aggression, sadism and psychopathy.
Interestingly, the study found that people who tend to like bitter foods such as black coffee or tonic water also had personality traits that could be seen as bitter and unpleasant.
Of course, not every single person who enjoys the bitter taste of kale is a raging psychopath ready to destroy your life, but you might want to pay attention to how your co-workers take their coffee in the morning.
Or better yet, maybe you want to take a closer look at how you take your coffee.