These five types of emails can sabotage morale, ruin relationships, and kill your office culture. Make sure you’re not setting a bad example. 
I’ve been using email for decades, but I’m still surprised at how many people don’t know the rules for the business use of email.
Specifically, there are five types of email that have no business in the workplace–ever. Let your employees know that you disapprove, and be sure you’re not setting a bad example yourself.
1. The Rant
It’s always a bad idea to write an email when you’re angry or upset. You almost always end up using words and phrases that you’ll later regret–and it’s all too easy to hit “send” in the heat of the moment.
2. The Scandal Sheet
Office gossip is ugly enough on its own; it doesn’t need to be accelerated electronically. Here’s the rule: Never send an email that contains anything that you wouldn’t want everyone to know that you said.
3. Marketing Spam
Any mass emailing where the recipient has not specifically requested to be on the list is a nuisance. Only send marketing emails when there has been a specific “opt in.” An “opt out” isn’t good enough.
4. Bad News
Whether it’s a firing, a resignation or a difficult reassignment, you need to deliver the blow either in person or (if that’s not possible) on the telephone. No exceptioins: It’s cowardly to use email to avoid dealing with other people’s emotions.
5. The Time Waster
Any message with a subject line that reads something like “thought this might interest you” is a waste of time. Don’t stuff your colleagues’ mailboxes with content unless you’re absolutely certain it’s relevant.