Your email program probably warns you about spelling errors. But it won't warn you about typing the wrong word, and you can type really awful wrong words in email. I've prevented myself from sending all but one of these:
Sincerely Yours, Toy [instead of: Toby]
Dead Ralph, It was nice to hear from you ...
Jane, I'm glad to see you're woring on this problem.
Alice, just a grief reminder ...
Jim, I haven't heard from you in a whine.
I reviewed your plan. It sounds goof to me.