What's the worst typo you have ever made, received or come across?

[J R Hartley]

An employee of one of the companies I deal with called one of my co-workers a twat in a reply to all email when he meant to send it to one of his colleagues.

We had this one customer who was always complaining and was forever kicking off and of my colleagues replied to his latest email rant. “Here we go again. Light the blue touch paper and watch the fireworks commence” and replied to all recipients in error.

Needless to say fireworks did well and truly commence

[JumpersforGoalposts]

Not strictly a typo but working overseas some years ago I set myself the task of getting at least a dozen or so e-mails a week done in the local language. Unfortunately one early example regarding someone's promotion that should have started "I am pleased to announce..." somehow became "I am pleasured to announce.."
THREE days of giggling before anyone explained!

[Taunton Blue Genie]

I used to work with a lady whose surname was Quinn. You can guess how it was misspelled in the Taunton phone directory.