Most people are pretty easy to get along with. They can see how it’s in their own best interest to communicate, uphold commitments, and maintain relationships. After all, it makes life and work so much easier and more pleasant—which is how people generally like work and life to be.

But all of that goes out the window when you are dealing with someone who is the literal worst. They seem to thrive on conflict; they’re so alienating that most of the time they don’t even end up getting what they want; their behavior isn’t rational, but they can’t stop. Because they’re the worst.

Much as we’d like to avoid such people, in professional life we don’t always get that choice. So here are a few types to watch out for, and some tips for dealing with those who are just plain awful:

People who are consistently dishonest

We tend to associate dishonesty with lying, but truly dishonest people wield their power in a far more subtle way: by withholding and altering facts so that others can’t effectively navigate the world. Dishonest people hope that by destabilizing our sense of reality, they will be able to control people and situations more easily. When someone blocks crucial bits of information or scrambles the info we do have so that it no longer makes sense, we come to question ourselves and others, and will fumble around to get a foothold on what is really happening—leaving us vulnerable to manipulation by the very person who made things unclear in the first place. So if you notice that someone is always knocking you off your game by needlessly introducing doubt and confusion into all kinds of situations, this is a red flag! Don’t rely on these people for intel; if you need information go straight to the source. These people have no power over us when we let the things they say go in one ear and out the other.

People focused solely on themselves

Someone who does not understand that getting along with people is about give-and-take is so self-absorbed that they are actually out of touch with reality. Worse, they experience not getting their way as a personal assault. When these people make entitled demands, it’s tempting to just ignore them and do your own thing. But a clever maneuver on their part turns you into the bad guy (“I don’t know why ___ never responds to my emails; he has something against me even though I volunteered to work on his project!”). The passive approach also leaves space for them to re-frame failure to comply as failure to communicate, which drags situations out (“Maybe you didn’t understand my last email; what I was trying to say is that I want to work on your project so please send the files asap!”). With these people, the direct approach is the only way. Be clear that you have heard and understood what they want—and that you aren’t going to do it. This won’t change them, but it will train them. They may still see you as their toy, but they’ll realize you are broken and will stop trying to play with you.

People who are utterly incapable of accepting responsibility

This person never accepts feedback without giving some in return, and never encounters criticism without shifting blame onto someone else. There are many flavors of this behavior: some people will lash out when pushed to be accountable for their actions, while others will mope like a dog with their tail between their legs. But whatever the reaction, it will never be “You’re right, I dropped the ball on that one—my bad.” These folks make confronting them so unpleasant (because they redirect blame, make excuses, and cast themselves as victims) that eventually most people will stop even bothering to engage. So the important thing to realize is that you can’t do this alone; no single person, no matter how respectful, assertive, or direct, can make someone who lacks a certain kind of maturity take responsibility for their actions. This is a battle of attrition, and they know it (it's how they've gotten this far while being the worst). So instead of letting them win, call in reinforcements. Ask your co-workers and supervisors for support in asking for—and if need be, demanding—accountability. Don’t stop trying, but don’t get stuck being the only one who is still trying.