You can lose your job for capitalising e-mails.
(Yes, it's true. A woman in New-Zealand lost her accounting job after sending "confrontational" e-mails filled with block capitals. On the web, capital letters are commonly thought to be online shorthand for shouting. Seemingly this lady had also highlighted phrases in bold or red. She has since been awarded $17,000 for unfair dismissal, so any bosses out there might want to reconsider.)