Apple's reputation rests on building 'user-friendly' systems. But of late I've been very annoyed with the poor quality of Apple error messages. I was trying to send an e-mail yesterday and the Mac mailer complained 'One or more of the "To" addresses appears to be invalid.' 'One or more'? How about telling me which 'one or more'?! The programmer who wrote the message generated because a specific address parsed wrong. So let the user know where the problem is!
Similarly, I was backing Garage Band files up to a CD and got the message 'The total size of the files you have selected exceeds the capacity of the target CD.' (I quote from memory here.) The programmer who wrote that one had just done a subtraction of the total size of the selected files from the CD capacity to see if they would fit. In other words, he had the precise amount of the excess sitting right there in his code when he wrote the error message. So, is it a proprietary secret, or could the user be informed as well? It really would have helped to know if I was over by 1%, 10%, 100%, 1000%, or whatever. Instead, I had to de-select one file at a time and try to burn the CD again, until at last it worked.
And those aren't the only two messages of their ilk. 'A modem error has occurred' comes to mind at the moment (which error?!), and I know I've seen others.