The Cost of Toxic Workplace Behaviour (And Why It’s a Performance Issue)

There’s a truth about me that probably won’t surprise anyone who’s spent more than five minutes in my company. I’m an extrovert. I get energy from people – understanding them, connecting them, and watching a room go from polite silence to something that actually feels alive instead of a hostage situation with biscuits.

Which is why it’s always slightly ironic when I find myself locked away for hours in my home office, working away with only my fat ginger cat and ChatGPT for company. My wife is also at home, but I’m mostly summoned as a part-time tea barista for what has somehow become a 12-blend operation that could rival a boutique in Woodstock.

Over time, and across more businesses than I care to admit publicly, I’ve learned something important about how I work best. I need to be in environments where I can both draw energy and give energy, where I can contribute to momentum, not just output. In high-performance, high-pressure environments, that matters more than most people realise, because when things get hard – and they always do- teams don’t just run on strategy or process. They run on energy.

Some people add energy into a system. Others take it out, and the impact compounds quickly. And the cost of that second group is measurable, particularly when it shows up as toxic workplace behaviour.

I’ve even found myself, on more than one occasion, being what you might call the “Personality Hire.” The “Glue Guy” – and there’s no apology attached to that. As Shawn Achor, Author of The Happiness Advantage, puts it, the people who actively invest in relationships become the heart and soul of a thriving organisation – the force that drives teams forward. If the work is getting done and you’re still bringing that kind of energy into a system, that’s not something to downplay. It’s something to lean into.

And it turns out that role matters more than people think.

We were lucky and privileged enough to have a break in Mauritius recently. Ever been to a silent disco? Now imagine a resort full of strangers who would rather fake a phone call to their imaginary dog than be the first person to dance. This guy changed that. Ten minutes in, the German who had been on Mojitos since breakfast was belting out “Sweet Caroline” into the void like he was auditioning for Oktoberfest: The Musical, while everyone else danced like no one could hear them – which, technically, they couldn’t. It was chaos. It was absurd. It was beautiful.

And it worked, not because of what he was doing, but because of the energy he was creating. People showed up differently around him – lighter, more open, more willing.

Which got me thinking: if some people add energy into a system, what about the ones who consistently take it out? And more importantly, what does toxic workplace behaviour actually cost organisations?

What Toxic Workplace Behaviour Actually Looks Like

Before this turns into a neat little BuzzFeed quiz called “Which Toxic Colleague Are You?” it’s worth being clear about something. The research doesn’t support clean, fixed personality types. There is no official handbook of “toxic people” [Source].

What it does show, consistently, is that certain patterns of behaviour repeat across organisations. Once you see them, you can’t unsee them.

Common signs of toxic workplace behaviour include:

• Controlling, fear-based behaviour: meetings become monologues, decisions are made before discussion, and autonomy slowly disappears like your will to live in a four-hour status meeting. What looks like “high standards” is often just fear in a blazer.
• Defensive, low self-awareness behaviour: feedback is treated like a personal attack, blame is passed around like a game of corporate hot potato, and eventually people stop raising issues – not because they don’t see them, but because they enjoy peace.
• Chronic cynical negativity: not loud, not dramatic – just a slow, steady leak of energy. Every idea is met with “yes, but,” every plan is doomed before it starts, and every conversation leaves you feeling like you’ve just eaten a bag of wet sand.
• Talented but toxic contribution: high output, low collaboration. The person who delivers results but leaves a trail of emotional wreckage behind them.

Most of this behaviour isn’t intentional. It’s learned, adopted, and often used as protection when people feel under pressure or out of their depth. But until someone develops the self-awareness to see it, they have very little ability to change it [Source].

At that point, toxic workplace behaviour stops being an individual issue and starts becoming an organisational one. This is not a personality issue – it’s a performance issue.

Where Toxic Workplace Behaviour Gets Expensive

I’ve seen this play out up close. I worked with someone who was more senior to me but deeply uncomfortable with how quickly I was moving across teams. In the time they’d been there, I’d moved through three teams and two promotions. I wasn’t after their role – I was after alignment so we could do better work – but nothing shifted.

I remember sitting in a meeting where they were briefing a creative team. The team came back with a very reasonable question: “Why?” And everything unravelled. What followed was one of those slow, painful meetings where the answer never arrives, just repetition, authority, and a slightly sharper tone each time the question is asked again. It was like watching someone try to assemble IKEA furniture without the manual, the tools, or the emotional stability.

And I remember sitting there thinking that this wasn’t about the work anymore.

Because the truth was – they didn’t know. And instead of stepping back, they doubled down. On control. On authority. And eventually, on gossip. The irony with gossip is that when everyone’s reputation is apparently the problem, the common denominator becomes obvious.

They left not long after, and when they did, something shifted almost immediately. The work improved, the collaboration improved, and the personalities improved. It was like removing a harness we didn’t realise we were wearing.

And this is where it stops being interesting and starts being expensive.

That experience isn’t unique. It’s supported by a growing body of evidence that shows toxic workplace behaviour has measurable impact on performance. When individuals experience even low-level disrespect, many reduce their effort and the quality of their work, and some leave altogether [Source]. Employees exposed to higher levels of toxic behaviour are significantly more likely to experience burnout, which is strongly linked to attrition [Source].

More broadly, toxic workplace behaviour is a stronger predictor of people leaving than compensation [Source]. Even at an individual level, avoiding a toxic employee can create more value than hiring a top-performing one [Source].

This is not a soft issue. It is a performance issue.

How Toxic Workplace Behaviour Spreads

Toxic workplace behaviour doesn’t stay contained. It spreads through teams in predictable ways. People watch what gets tolerated and adjust accordingly. If interruptions are common, people speak less. If blame is deflected, ownership disappears. If behaviour is undermined through side conversations, trust erodes and collaboration becomes guarded [Source].

Over time, these adjustments compound. What begins as individual behaviour becomes a shared norm. Meetings get worse, decisions get slower, and honesty becomes selective. The most dangerous part is that it rarely looks dramatic – it shows up as slightly worse meetings, slightly less input, slightly more fatigue – until one day the system hasn’t broken, it’s simply been quietly downgraded.

What Needs to Change

Organisations need to treat toxic workplace behaviour like any other performance risk, because the cost of ignoring it is consistently higher than the cost of addressing it. If you’re leading a team right now, the question is simple: what toxic workplace behaviour are you currently tolerating?

This doesn’t mean removing people at the first sign of difficulty. It means recognising behaviour early, addressing it clearly, and supporting the development of self-awareness where it’s possible – and being honest about where it isn’t.

Because self-awareness is an individual problem.

Toxic workplace behaviour is an organisational one. The moment it’s tolerated, it stops being about one person and starts becoming part of the system.

And if you don’t think this exists in your team, ask the Glue Guy. They’ll have felt it long before anyone else was willing to name it.