Four types of toxic colleagues, and how to actually deal with them

A few weeks ago I was interviewed for a piece in the ‘i newspaper’ about the colleagues who quietly make our working lives harder. It got such a strong response that I wanted to write more about it here, because in twelve years of coaching, this is one of the things I hear about most.

Not the big dramatic conflicts. The smaller, drip feed stuff. The colleague who leaves you second guessing yourself. The one whose mood you can feel the second they walk into a room. The one you're always slightly bracing for.

According to Acas, 44 per cent of working age adults in the UK experienced conflict at work last year. That is nearly one in two of us. So if you're dealing with a difficult colleague right now, you are absolutely not the problem, and you are definitely not alone.

Here are the four types that came up in the piece, including the three I was asked about directly from my own coaching experience, and what actually helps with each one.

The Passive-Aggressive Operator

This is the colleague who sounds supportive while quietly undermining you. Something like "that's almost right, don't worry, I'll fix it" said with a smile. You come away feeling like you should be grateful, when actually your confidence has just taken a small hit.

What helps: name the behaviour calmly and directly, without matching their tone. Something like "I noticed you offered to take that over in the meeting, I was happy to finish it myself, so let's agree who owns it going forward" does far more than letting it slide.

The Corporate Narcissist

I've worked with plenty of these over the years. The colleague who dominates every conversation, talks over people, and makes it hard for anyone with a quieter style to get a word in. I remember working alongside someone like this myself, and how demoralising it became. After a while you start to wonder what the point is in even speaking up.

What helps: claim your space early and simply. "Can I just finish my point" works better than you'd think. If it's a pattern rather than a one off, it's worth raising with whoever runs the meeting, so there's a clearer structure that gives everyone airtime, not just the loudest voice in the room.

The Mood Hoover

This is the person who meets every idea with a reason it won't work. They think they're being sensible. What they're actually doing is slowly training everyone around them to stop bothering to share anything new. I've experienced this myself, to the point where I started filtering my own ideas before I'd even said them out loud, especially the more creative ones.

What helps: get specific about what you actually need from the conversation before you have it. "I'm looking to explore ideas at this stage, not reasons it might fail" sets the tone before they get the chance to derail it.

The Defensive One

This is the colleague everyone tiptoes around. Feedback lands badly, accountability disappears, and small issues can escalate fast. I've coached clients through exactly this, including situations that felt more like playground politics than a professional environment, with things said behind backs or taken straight to senior leaders rather than raised directly.

What helps: keep your own communication calm, factual and unemotional, and bring things back to shared goals wherever you can. You can't control how someone else behaves, but you can control how steady you stay in response. And if it's genuinely affecting the team, it's fair to escalate it.

The pattern underneath all four

Every one of these behaviours only continues because it goes unaddressed. Not confrontation, just clarity. A calm, clear sentence said early nearly always saves you months of quietly absorbing something that was never yours to carry in the first place.

If any of this sounds familiar and you'd like to think it through properly, this is exactly the kind of thing I work on with clients, whether that's one difficult relationship or a wider pattern that keeps showing up at work. You can read more about coaching with me here, or get in touch for a chat.