how do i handle petty behavior between two employees who don’t like each other?

A reader writes:

Where is the line between what is and what is not acceptable when talking about pettiness between colleagues?

I’m dealing with two employees on the same team who just don’t like each other for a variety of reasons. Fortunately, these two don’t have to work together very often, but stay in the same suite. Both are big personalities, have strong opinions, and both can become powerful. Other than advising them to be aware of how they interact with each other, I don’t know how to address the pettiness they’ve both adopted from the “you both need to stay professional with each other” perspective – things like good from everyone on the team except the other, ordering dessert for “who wants” with ingredients the other is allergic to, not holding the door open for the other “without realizing they have been there”. It’s hard for me to figure out where the line is between “you’re not meeting the expectations of proper behavior” and “come on, just don’t be stupid”, especially when someone claims things like “you can’t ban me from ordering dessert that- I want it and offer the rest to others.”

Their work performance is quite solid. They are both passionate about the work they do, execute it well, and are (for better or for worse) both kind of “core” of the team (subject matter experts and likely committed to being with this company for a long time time).

The approach is to focus on the desired outcome, i.e. “no one on the team can say you don’t like person X”. They can sense however they might want to about each other, but if others pick up on those negative feelings, that’s a problem — because it will make the work environment uncomfortable for everyone.

So yes, of course they can order whatever dessert they want, even if the other person happens to be allergic to it, and of course, sometimes they might not say goodbye to absolutely everyone when they leave…but more rather than getting stuck in those. details, focus on result you need from them, meaning they can’t make people feel uncomfortable with their behavior and they have to treat everyone with a basic level of warmth and pleasantness.

I would frame it like this: “You have to behave in such a way that you don’t make this a negative work environment for other people. If people can tell you don’t like Jane, you don’t meet that job requirement. If people perceive you as petty or vindictive, then you are failing at this. And I take that very seriously – it’s an absolute requirement to be on this team that you treat everyone with respect and not make the rest of the team uncomfortable. Unless you really need me to give examples, I won’t go through the pettiness I’ve seen example by example; I assume you understand what I’m talking about. It has to change if you want to stay in this team.”

And you should stand firm on that line. Solid work performance or not, you can’t keep people who behave like this. It poisons the environment for the entire team… and at some point the rest of your staff will start to worry how they want be dealt with if they somehow end up on the wrong side of one of these employees.