The warning signs of a toxic boss (and what to do if you have one) Think you may be dealing with a toxic boss? This flow chart might help you find out. Working life has been hard enough over the past 12 months, and the last thing you need is a leader who makes it worse. A toxic boss can negatively impact the quality of your immediate work and wellbeing, but can also have long-term effects on your career. Barbara Kellerman, a lecturer in public leadership at Harvard University and the author of Bad Leadership, has said that “bad leaders are more similar to good leaders than they are different”. According to Kellerman, both good and bad leaders are intelligent and have high levels of energy, a strong drive for power and achievement, decisiveness and determination.