I have a secondary requirement (or strong wish) for emails I receive: USE PROPER GRAMMAR, especially the correct use of:

-- Their, There, They're

-- Your, You're

-- To, Too, Two

and so on.

This is in addition to the prerequisite spell check, of course.

I think the biggest transgression is the misuse of There/Their/They're. I see that one entirely too much - and pretty much everywhere people use written communication.

The problem with this type of transgression is that I tend to get distracted when it is encountered. It takes my focus off of the content and intent of your email, and switches it to me mentally bitching about it, and lowering my impression of the sender.

The written word is an incredible tool for communication; and we should strive to use that tool correctly, if not for our own sake then for the sake of others. Not doing so not only lowers my impression of you, it also leads me to believe you don't hold me in high regard, either. If you did, you would strive to communicate in a clear, efficient, and correct manner.