Through a friendly tone, a personal question, or simply a smile, you will encourage your coworkers to engage in open and honest communication with you. It's important to be nice and polite in all your workplace communications.
This is important in both face-to-face and written communication. When you can, personalize your emails to coworkers and/or employees – a quick "I hope you all had a good weekend" at the start of an email can personalize a message and make the recipient feel more appreciated.