There have been a lot of articles about bullies in relation to schools and often in relation to the Internet (ie: Trolls). But, even though we're (technically) all adults, bullies do grow up and sometimes stay bullies, and don't bully just in the safety and anonymity of the web. Sometimes they take their bullying ways to work.
At the core, bullies are dealing with some kind of powerlessness inside of them. They had child hood trauma and never really learned how to feel powerful on their own, they may have learned to fake normal but never understand it, they may have poor impulse control...the reasons go on.
In a recent gig, for example, a perfectly nice gentleman who was a subject matter expert and well liked by the team went off the deep end one week and never came back. Something in his personal life flipped the switch and he took out his powerlessness on me and the rest of the team. When the situation was dealt with, he was first completely blindsided by the fact that anyone wielded the authority to stop his behavior, followed by chagrined and embarrassed at the behavior. He didn't believe, he said, we'd "be able to move quickly" at all, and that while he expected it would "come to this" he just never expected that we'd stand up to it so soon.
He was aware he was bullying us, and when he was stopped--and fired, because I fired him--he reverted to the perfectly nice person he'd been before. I think part of that was because of the way it was approached: we put the cards in his hands to change his behavior and keep the job, or to not change his behavior and lose the job. He chose the latter. But he was allowed to choose. This seemed to ail whatever powerlessness was in him. He actually thanked us for the opportunity, that he'd enjoyed working with us.
I'm not sure what caused him to test the rules of working for a company so thoroughly that he had to be asked to leave, but I know it was not a common behavior for him. His temper was always fast to flare, but actual bullying, not so much. As a manager, I tried to understand and help, but sometimes there are behaviors that cannot be helped. You can only go so far. Its the choice of the employee/co-worker/etc. to determine the final course.
And, as I've said before, doing things people don't like is a behavior, not an intrinsic thing like the color of your eyes, that you cannot change. Some people act like bullies, but they are not inherently bad people. If the behavior can change, they can change. If the behavior can't change, they may be able to find a place elsewhere that it is not as unacceptable or difficult, or where they may not feel the need to act that way at all.
If the bully at your office works for you, you can do what I did: meet with them semi-privately to discuss the behavior (and emphasize the behavioral aspects) and then clearly explain what you'd like to see instead. Some people learned the wrong lessons before you got them. Some people don't know their behavior is problematic. Some people are challenging you to see how far they can go. Whatever the reason, talk to them, tell them what is expected and how to achieve that. Note, I said "semi" privately. This is because someone who is bullying is at his/her best when they are one on one. Bring another trusted person to the talk. This will help you being intimidated as well as provide a witness to the proceedings.
On the first talk, I leave it at that. In the case of this employee I mentioned, since he spent part of that conversation literally yelling in my face, I wrote it up immediately. I strongly suspected it was going to happen again. If you think there's a chance it might--even a faint one--write it up and send it off to your boss. Documentation is a good protector if there is ever a he said/she said moment in the future, as is bringing a guest with you to the discussion who has a reason to be there.
Also, as one of my former bosses, he has a "no asshole" policy. Which is to say, if someone's being or acting like an asshole, get rid of them right then. You do not have to tolerate bad behavior if it is extreme enough. In the example where my fired employee screamed into my face, no one would have blamed me for firing him on the spot. However, I operate on the "everyone has a bad day" principle, whereby sometimes bad stuff happens and you react to it and you react all over the first poor unfortunate person you encounter. So I wrote it up, and left it alone.
If the initial talk doesn't bring about improvement, escalate. In this case let your boss and HR know you're going in again, and list what you'll talk about, specific examples, and actions you want to see taken and by when. Go in, again, preferably not alone (again) and go over it. The "by when" is the first chance they have to improve their behavior by a set period of time. Afterwards, write up what happened and what was said, and send that out.
If the time comes and goes with no improvement, or the situation escalates even further (in my case, my employee was starting to bully the other employees), take swift and immediate action. Remove them from the situation. Document what happened. Talk to your boss about whatever is appropriate from time off without pay to termination. Then follow through.
So many people do not want to follow through on corrective actions, for bullies or any difficulty with an employee. Failing to follow through will only increase the bad behavior. It may make you feel sick to your stomach to fire someone, but sometimes, you have to do it or the situation will actually get worse.
In the event your bully is a co-worker of equal standing, similar rules apply: talk to them first. Ask for improvement. Write up what was said. Repeat this process. In the event the second talk doesn't work, either, escalate to your manager and human resources.
In the event your bully is your boss, apparently you're not alone. Per a recent study, bosses who bully you may not just be bullying you, and their bullying of you affects the entire department. The results per Forbes: "...both abusive and vicariously abusive supervision had similar
impacts on employees, with both forms leading to more job frustration, a
greater likelihood of coworkers abusing one another, and a greater lack
of confidence in the company as a whole..."
If your boss is bullying you, and you've read my earlier articles about the liability of being a manager, try not to rub your hands together in potential lawsuit joy too soon. Document every instances of abuse, who was there, and then meet with your boss to discuss a change in behavior. If you're afraid to meet with them alone, talk to HR about mediating a meeting. Document the conversation. Things are likely to get worse before (or if) they get better. A bully doesn't like to be bullied. But, usually, involving HR and setting up specific boundaries and clear expectations can make for a tolerable work environment.
If it doesn't, you can work with HR regarding the behavior; this may end in the termination of your boss, or in you looking for work elsewhere. As noted previously, Human Resources is there to protect the company. They are not your friend. They are not your bully boss's friend. So tread carefully.
Finally, if you find that your bad moods are coming out all over your employees, stop it. Don't wait until someone asks to talk to you (with or without HR) about your behavior. Feel your frustration rising or the desire to call someone a bad name or hit something? Take a walk. Leave the situation. Doesn't matter if it's a big important meeting, you losing your cool is so much worse than missing a meeting. Analyze what's going on in your life to make you feel powerless and lash out, and try to get a handle on it. If you can't on your own, your HR folks are likely to be able to provide you with health care information where you can work with someone to avoid being the bully boss. Because, no one likes a bully, most especially the bully him/herself.