Employees are increasingly communicating to each other via email or text messages. Today’s best managers know that email and text messages typically don’t accurately portray the emotions of the person sending the message. Because of the lack of cues (facial expressions, eye contact, etc.) in electronic messages, receivers tend to believe that the message is more negative and/or more neutral in tone than was intended. To help message receivers accurately understand your emotions in electronic messages, specifically state your feelings in writing. For example, write that you are happy that the employee liked your idea.
Source: Byron, K. 2008. Carrying too heavy a load? The communication and miscommunication of email. Academy of Management Review, 33, 309-327.