It’s always nice to see a useful bit of UX in action. I was using Google mail only a few minutes ago; penning an email to someone with which I was intending to add an attachment. As you might expect I added the words “I’ve attached” to the body text, finished the email and promptly clicked Send, neglecting to add the file.
Google pops a small message alerting me to the fact that I had said i was attaching something but no attachments exist! Genius! I could then stop the send, add the zip file attachment and send again with my email fully complete.