What is the best example of "the road to Hell is paved with good intentions" in history?

1. The invention of the trans-orbital lobotomy was initially hailed as a major advance in the treatment of mental illness, even getting its inventor the Nobel for medicine. Only later did we start to really grasp what we were doing to people.
   — PruneTheMindsGarden


2. When the mollusk fishermen tried to protect their fisheries from starfish, they would catch them, chop them up, and dispose of them back in the sea. What they didn't know was that not only can starfish regenerate new legs, but the severed legs can also regenerate a new starfish. They made the problem 100X worse.
   — Scrappy_Larue


3. Several time in history, when there was an invasion of a pest or another (rats, snakes, and such) a politician thought it was a good idea to motivate the population by giving them money for each dead animal they would bring. Every time people would realize it was more cost effective to breed the animal in a cage rather than go out in the wild to catch it.
   — inckorrect






4. When radium was first discovered, it was all the rage, being new and « full of energy » So they started marketing radium cream, make up, radium pills etc I remember an old poster for « France ‘s most radioactive water! Tested by Professor Curie »
   — Pippin1505


5. Forest fire suppression. We wanted to save all of the nice trees and animals from forest fires, so we invested a ton of time and money into stopping forest fires. Turns out all that did was turn our forests into tinderboxes. The occasional fires that would clear out dead debris and germinate pinecones became infernos that destroyed entire forests. Turns out that small forest fires are healthy for the forest. Our bad.
   — FastFourierTerraform


6. Mao Zedong's four pest campaign. The Sparrows were eating all of the crops. Mao had the genius idea to get everyone to go out and kill all of them. Once the Sparrows were killed, the insect population in the region boomed. The insects swarmed and ate almost all of the crops in China. This was one of the factors to the great chinese famine which killed around 45-75 million people.
   — badusername672






7. I'd say Prohibition, to be honest. Americans drank *a lot*, and it was arguably a legitimate social problem. But banning all drinking ended up creating corruption, organized crime, and a whole host of other social issues.
   — anyyay


8. Doctors in the 1950s prescribing Thalidomide for morning sickness during pregnancy. It was this great new drug...until it wasn't.
   — anyyay


9. [This poor guy.](https://en.wikipedia.org/wiki/Thomas_Midgley_Jr.) Thomas Midgley was a chemical engineer born in 1889 who helped invent CFCs (which destroy the ozone layer) and then later helped develop leaded gasoline (which made generations of people slightly dumber and caused lots of other side effects). He died in the fifties and never found out what horrible disasters he helped cause.
   — autoposting_system