User eXperience - Fail, why?

This is a collection of examples of gross failures of a programmer to communicate - inform, direct the user as to what has happened and what options are available from this point.
One of my favorite examples comes from Novell:

G: is already connected to \\BRD-SRV1\PROJ1.

Do you want to connect G: to \\brd-srv1\proj1 instead?

 

I get that there was a problem. I doubt that it was really a case problem (it's MS Windows XP, after all.) But what are my options? Try again? Abandon what I wanted to do - perhaps just walk away?

A useful message might have told me the real reason the original drive mapping operation failed. Even if the dialog explained that an unknown error happened and ask if I want it to try again, it would be useful. Of course if another failure happens, I expect a more useful explanation.

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Tosh