She cannot hear you either. She cannot hear you laughing. She cannot hear the flirtatious tone in your voice.
All of the essential nonverbal communication that takes place when you talk to someone is missing in email. And, as we all know, more important than what you say often is how you say it. The information encoded in the tone, mimics and gestures is lost.
The Case of the Missing Undercover Information
Of course, most of the time we do not know that we are sending sublime messages alongside the pure verbal communication. We do not know it with a good reason: we would not want to tell it.
Still, this information is essential, and there is a lot we do want to tell about how we feel.
If all the undercover information that goes with a message is missing, this is destined to be a source of formidable misunderstandings. Misunderstandings can always happen, often they are funny, but they can also make life extremely difficult.
Imagine receiving an email that says: "And, btw, I'd love to eat you." If you are not sure concerning the nature of your girlfriend's intentions (are they are cannibalistic or quite obvious?), you'll pause for a moment, stunned and irritated.
Not Everybody is Shakespeare
When you write an email, you can use language to express your feelings. Depending on how gifted you are as a writer, your mileage will vary. The email above could read like: "And, btw, I want to eat you, and I hope you enjoy me, too." Or maybe: "And, btw, I want to eat you. (That was a funny remark)"
Using the means of language is difficult when it comes to emotions, and it is often unnecessarily cumbersome. That's why a shorthand has developed. They are called emoticons or smileys, and they offer a great way to convey emotions via email.