When I reply to an email in Outlook 2003, the display of the original email in my inbox updates with the helpful annotation, "You replied on 2/6/2009 at 2:41 PM." That's fine.
What sucks, though, is that Outlook applies that annotation before I've actually sent the reply. There's a time period when I'm composing the reply during which Outlook claims that I've sent a reply to a message, but I I haven't actually replied yet.
Ways in which this might be disastrous are left as an exercise to the reader.