[scoofy]

Probably the proliferation of opiates and, more likely, methamphetamine. Scientific progress that makes these highly addictive and debilitating substances easy to produce can't be undone.

I live in San Francisco, where it now costs over $100,000 per year to operate a single toilet, because without it being under constant guard, people start living in them.

[greenavocado]

A more efficient solution is to have a stainless steel bathroom which rinses itself with bleach every 20 minutes unless an emergency call button is activated. If it is occupied past 20 minutes a hydraulic press ejects the contents of the bathroom to the outside.