This makes email a unique medium. The lack of nonverbal clues makes it easy to misinterpret something, but we're not careful enough to avoid these misinterpretations because email feels so instant, easy and accessible, just like talking.
As a general rule, you should assume:
- What can be misunderstood in an email message will in fact be misunderstood,
- no matter how many winking smileys you add.