Things that bug me.
Things people put in writing:
"I just wanted to share the following . . . " (Just now? This is it? You won't write again? Promise?)
"We'll need five (5) of those for the two (2) locations." When words alone are not enough, add the number.
"Just a reminder that <information never shared before because I forgot>."
Things people say:
"I could care less." (I couldn't.)
"That's not professional!." (How would you know?)