Necessary Invention: Anti-Labels

Every time I add a label to an item in Google Mail, Windows Music Player, or what have you, the system should automatically add an "anti-label" to all other items indicating that they are NOT in the label group.

Unless I have literally only created exactly one label (so I can view all item without the label) or two labels (where all of my items are either labeled A or B, but never both) how can I find all mail items that are NOT relevant to my work? When playing music, how can I play all items whose genre is NOT podcast or comedy? I shouldn't have to select all items in every other genre, as well as all the music I haven't yet labeled.

As far as technical issues, adding a label X to an item should automatically remove the anti-label "not X". An anti-label should disappear the moment the last item with that label removes it, so, for example, if I accidentally create a label for a music item called "grudge", and then quickly delete the label and add a new label "grunge", the anti-label "not grudge" should go bye bye and the new label "not grunge" should be created. If "not grudge" has already been used for some kind of filter mechanism, it can be silently deleted from that mechanism. It would have been better form for me to simply rename the label "grudge" to "grunge", which will automatically rename the anti-label "not grudge" to "not grunge".

Thank you and good night.