When good leaders go too far: the dark side of personality at work

Adrian compared personality to height. Being average has advantages, and very tall or very short people face practical problems. Personality works the same way: the further someone sits from the middle on a trait, the more distinct both their strengths and their weaknesses become.

Extraversion is the clearest example. Extraverts build large networks, enjoy people-focused roles, and come across as socially confident. At the extreme, they trade accuracy for speed, take impulsive risks, and can become attention-seeking. Introverts face the opposite trade-off. Many successful leaders are what Adrian calls socialised introverts, who have learned extraverted behaviour but find it draining.

Adrian argued that organisations still overvalue extraversion without seeing its downsides, and that the dark side of personality is simply the bright side taken to an extreme.

Adrian walked through the remaining Big Five personality traits:

• Neuroticism: low neuroticism, or high emotional stability, is generally better because it brings resilience. People with moderately high scores tend to be vigilant and emotionally literate. At the extremes, very stable people can struggle to read emotions, and very unstable people become fragile.
• Openness to experience: openness brings curiosity, creativity, and imagination. At very high levels, people can come across as eccentric and hard to work with. Very low scorers tend to resist anything new. Adrian noted that openness is not among the strongest predictors of work success.
• Agreeableness: agreeable people are warm, kind, and popular. The research shows agreeableness is negatively correlated with success at work, because highly agreeable people may avoid tough decisions such as letting people go. Some disagreeableness helps, but at the extreme it shades into callousness.
• Conscientiousness: conscientiousness is the best single predictor of workplace success. At very high levels, it can become rigid perfectionism and workaholism.

The typical profile of success at work leans towards extraversion, emotional stability, openness, lower agreeableness, and high conscientiousness. Most people have one or two scores well above or below average. Hiring often means trading off someone's extremes against what they bring, such as a highly creative person who is interpersonally difficult.

Teams add another layer. Professions attract similar personalities, and Adrian cited attraction-selection-attrition theory to explain why groups of accountants, engineers, or salespeople often look alike psychologically. That homogeneity is understandable, but teams still need variety.

Leadership brings power, influence, money, and prestige, and Adrian's question is which of these attracts a candidate. Too many power-hungry people have been drawn into leadership roles, which explains the growing interest in humble leadership.

The stakes are high. Adrian estimated that around 40% of people appointed to senior management positions derail, by being too slow, too bold, or too willing to take risks. Organisations invest heavily in assessing leaders and still get it wrong often, partly because interviews favour some personalities. Introverts and agreeable people don't always interview well.

Alongside psychometric assessment, Adrian asks three questions that conventional selection often misses:

1. What is the person's history of relationships? Leaders who derail struggle to build and sustain healthy relationships at school, university, and work.

2. How self-aware are they? Compare how someone expects to score on a personality assessment with how they actually score. Large gaps are a warning sign.

3. How well do they adapt to change? Business changes fast, and adaptability tends to decline with age.

Of all the ways to assess people, Adrian considers observational data, gathered through 360 feedback, one of the cheapest and most valuable. Different people see different sides of you:

• Your staff know your weaknesses, your foibles, and how you behave in a bad mood.

• Your colleagues know your abilities and your values, often as competitors.

• Your clients see how you perform where it matters most to the business.

• Your boss mainly knows your output, and Adrian considers the boss the person who often knows you least.

That makes multi-source feedback valuable for both external and internal appointments, especially for succession decisions. It is often where the first clue about a problem appears. Emma added two practical requirements: a trusted partner with a well-designed questionnaire, and secure data handling, because some respondents hesitate to give feedback electronically.

On the objection that 360 is expensive, Adrian's answer was blunt. Compare it with the cost of removing the wrong person from a senior role.

The data won't always fit together neatly, and someone may behave very differently in different settings. Adrian sees that as the nature of people rather than a flaw in the data. The aim is to predict how someone behaves across situations.

Asked which traits organisations should watch most closely when selecting or promoting leaders, Adrian named two:

• Super self-confidence: a spectrum that runs from healthy self-esteem to arrogance and subclinical narcissism. Leaders at the extreme make everything about themselves rather than the organisation.

• Low morality: very low agreeableness combined with no conscience or guilt about mistreating others.

These leaders still get promoted because they are often charming, articulate, well-educated, and backed by a record of success. Charm switches off our radar, which is why background information matters so much. Adrian recommends checking a candidate's history and what other people say about them.

When reports suggest a leader is showing extreme behaviour, Adrian's first rule is to gather reliable multi-source data. Make sure the problem isn't one disgruntled individual, and establish whether the cause lies with the person or the organisation. Only then confront the individual.

Training and coaching help when the problem is a skills gap, such as running team meetings or coaching others. Adrian estimated this works for 10 to 20% of derailing leaders. Success depends heavily on self-awareness.

For the rest, organisations have three options:

• Surround the leader with a strong team that monitors and restrains extreme behaviour. This can work, but it takes time and money.

• Use fixed-term appointments or probation periods with a formal review.

• Remove the leader from the role. Moving them sideways only gives someone else the problem.

Adrian's closing recommendation was to separate selecting in from selecting out. Every hiring process lists the competencies it wants, and Adrian recommends that someone in the process is explicitly responsible for looking for evidence of the traits you don't want. He described it as having a good cop and a bad cop in selection.