27. Biometric ID

Biometric ID like your retina and finger prints could be used for many important stuff. If you scanned your finger or retina, and then stored in a computer or phone you'd risk losing this important stuff to hackers and criminals.

Your finger prints could appear in a crime scene without your knowledge.

Some important organizations used scanner of retina or finger prints in their office instead of scanning an ID card. Therefore, you don't want your unique retina and finger prints spreading over the Internet.