It would be easy to focus only on the positives of humor. After all, I’m encouraging humor in the workplace; telling you the good is part of the strategy to convince you to start using it. But it would be wrong to not mention the dangers of humor, like how it’s wrong to stand on the left side of escalators. (Look, if you want to use those 20 seconds to rest, great. Just do it on the right side, so those of us who want to rise more efficiently can.) Bob Mankoff, former cartoon editor at the New Yorker, says humor can “unite and divide, teach and taunt, attract and repel.”

Given this dichotomy, I would love to create an entire Jedi analogy around the light and dark side of humor, but that would imply that the good and bad create balance. I even hesitate saying humor is a double-edged sword (or lightsaber) because that also suggests two equal sides of good and bad.

Instead, I’ll say humor is like a screwdriver (Doctor Who fans, feel free to imagine a sonic screwdriver). A screwdriver is an incredibly effective tool that often involves a twist and, when used in the right context, can help you construct and deconstruct any number of objects. But, in order to get the benefits, you have to use it correctly. If you try to use a Phillips head screwdriver on one of those screws that looks like a star, it won’t fit. And though a screwdriver is meant to be a tool, you could try to stab someone with it.

Non-metaphorical translation: humor is a fantastic tool when used appropriately. When it’s not, it can have serious consequences.

Danger #1: It Can Distract People

Distraction can sometimes be a good thing. If you’re stressed-out at work and near the point of burnout, taking a break to recharge can be valuable (and might even be a strategy talked about later in this book). But distraction can also create disaster.

As Dr. Jim Lyttle shared in his paper on the judicious use of humor in the workplace, “While [humor] may seem harmless enough on a personal level, tomfoolery can lead workers to ignore quality or safety standards.” If you’re working in a factory and are too focused on your music, you could accidentally run into a wall or get hit by a forklift. Or if you’re working on a presentation, you might go down a rabbit hole of finding the perfect dog picture to include rather than focusing on building the rest of the content. Because humor is fun, it can keep people from focusing on the right things.

One of the first humor workshops I delivered at P&G was on using humor for innovation. The feedback after the event was that it was too fun. Too fun? That’s a thing? But to one person it was. “I had a lot of fun, but I don’t see how it’s going to help me do my job better.” I had failed to make a clear connection between the exercises and their impact—how making up words and defining them uses the same creative muscles as coming up with innovative solutions. I’ve since learned how to better connect the fun with its function.

Some people also use humor as an alternative to getting anything done. Humor doesn’t replace work. If your boss says, “Hey, do you have those TPS reports?” You can’t respond with a joke and move on. You actually have to do the TPS reports, Peter. (Shout-out to Office Space, still one of the best worst cinematic workplaces and the inspiration for red staplers everywhere.)

Humor can also be used to strategically create inaction. That’s why court jesters existed in a monarchy. A court jester was granted permission to poke fun at the court and point out its absurdities so that the onlookers would laugh, tension would be released, and the threat of revolt diminished. This still holds true today when, for example, joking about an inequality replaces actually rectifying it.

Danger #2: It Can Divide People

Humor has this incredible ability to bring people closer. When we laugh or smile together, we create a human-to-human connection. But it can also divide us.

“Although humor unifies, it also can divide by creating in- and out-groups and accentuating power differences,” says John C. Meyer, associate professor at the University of Southern Mississippi. If you’re not in on the joke, humor doesn’t create connection, it destroys it. The shared laughter of the in-group says, “We’re cool with each other but not with you,” like just about everything the Plastics do in Mean Girls. It can feel isolating and is a clear signal that “you can’t sit with us.”

It’s also why the dreaded “mandatory fun” can do more harm than good. Trust falls have become synonymous with team-building awfulness because they attempt to manufacture connection. For the people who just want to go home or would rather be focused on the work piling up on their desk, the experience that is supposed to bring people closer is only driving them further away.

Danger #3: It Can Disparage People

At its best, humor is a positive force for good. At its worst, it’s a tool used to suppress ideas, destroy self-esteem, and make people feel terrible.

“Disparagement humor can foster discrimination against targeted groups,” explains Dr. Thomas Ford, a researcher of prejudice, discrimination, and humor at Western Carolina University. “For prejudiced people, the belief that ‘a disparaging joke is just a joke’ trivializes the mistreatment of historically oppressed social groups.”

If you work in an environment where people are constantly made fun of or ridiculed, it changes your behavior—you’re less likely to share new ideas or to be yourself out of fear of repercussions. If you’re often the butt of a joke, it can damage your self-esteem. This is even true if you’re the one making the joke, which is why self-deprecating humor should be used with caution. This negative effect is compounded when leaders use aggressive humor. One study found that when leaders used disparaging humor, their employees were more likely to engage in bad behavior and were less likely to be engaged in their work.

Humor is a tool, and just like any tool, it can be used to create or destroy. Like anything with an associated risk, it’s important to understand its potential dangers, so they can be mitigated rather than ignored completely.I’ve dropped my phone on my toe at least 17 times in my life, but that doesn’t mean I’m going to give it up and start sending messenger pigeons (how would I send a gif?). Humor carries some risk, but the pros far outweigh the cons.