In this particular example, I was uploading a file (.dxf).
The error I got was "Import Failed".
Great, thanks. How about WHY?
Error messages are useless unless they give some indication as to WHY it's an error.
Was the file in an unsupported format? Was it a corrupt file? Was there something in there the sofware couldn't handle?
There are plenty more areas where the errors are just generic and useless.