Configurable Ear Plugs

  With unwanted emails it's easy: You can place any address on a "No thank you!" list, and you will never again receive an email from that particular person (unless he or she changes the address, but that's a different story). Wouldn't it be wonderful to have the same options for the "junk" that reaches your brain via your ears?
  Boys, just imagine: You can talk to your buddies without having to listen to what your girlfriend is telling you about her latest shopping trip. - Girls: Annoyed by that idiot sitting next to you at the bar who has been talking to you for more than half an hour, although you have showed no sign of interest? Just configure your ear plugs accordingly, and you will still be able to chit-chat with that handsome barkeeper.
  Or just imagine you are stuck in a train compartment on your way to an important meeting, and the baby next door keeps screaming all night. Or maybe you are the mother, and you do want to hear your baby, but not the voice of that idiot complaining...
  There would be infinite applications for this invention.