As any self-respecting obsessive-compulsive will tell you, you can't touch sink knobs. Because you turn them on when your hands are dirty, then wash your hands, then go to turn them off and re-encounter the germs you deposited on them ten seconds earlier.
Problem solved with the Miscea Sensor Activated Faucet! A wave of your hands turns the water on or off, adjusts the temperature and dispenses soap or disinfectant, all with a Bang-&-Olufsen-like total lack of contact. Sounds great, right? Too bad the dirty plumber has to touch it when he installs it--his germs will live on that thing forever.