I’m sure you followed the news a while back about the horrible cyber attack on Sony pictures. Tons of confidential information was hacked and released, including stuff like executive salaries, medical records, and film scripts. Also leaked were emails—including some mean, nasty, and utterly embarrassing ones between colleagues. I’m not condoning any of the content, but this is a good reminder that if you have anything negative or snide in your mind—like you think Angelina Jolie is a “spoiled brat”—do not put it in an email.

A professional friend of mine has a good litmus test she uses before she shoots someone an email. She asks herself how she’d feel if key people in her life—besides the recipient—were to read it: her boss, her colleagues, her husband, and even her pastor.

The reason you shouldn’t compose negative emails isn’t simply because your company might get hacked one day. Your own organization could very well be keeping track of what you’re sending. Courts have ruled that employers are generally free to read employee emails as long as there’s a business purpose for doing so—and some do it anyway. Even if you use your personal email address, your company may monitor your messages if they’re sent on your work computer. And here’s a really scary fact. Some employers use “keylogger” software that enables them to see drafts of emails that you never actually sent. Ouch.

Okay, you may be saying, I get it. But what about legitimate business emails that may require a stern tone or an edge to them? For instance, let’s say you want to send a message to a subordinate who is slacking off or a colleague who’s trying to undermine you. How do you handle those?

I have three rules for that type of email.

1. When you’re drafting the message, do not type in the recipient’s address. It’s too easy to accidentally hit send before you’ve finished composing your thoughts.

2. Sleep on it. At the very least, let several hours pass, giving yourself a chance to cool down and come back to the material with a fresh eye. Is this really, really what you want the person to read? Will you feel the same way in three days? What are the possible repercussions? Could it backfire on you?

3. Here’s the most important tip of all: Don’t send that email. If you have something serious to say to a subordinate or colleague, it’s far better to do it in person. It’s easy for emails to be misinterpreted. Plus, a pissed-off recipient could share your email with others, an outcome you probably don’t want.

Instead, simply use the draft you created as way of gathering your thoughts and/or letting off steam. Then arrange to talk to the person face to face. It’s not as easy, but the end results are likely to be far better.

Trust me, there are some emails I wish I’d never sent.