SUCCESSFUL FAILURE

Scientists at Pfizer , a pharma company tested a new drug for Angina - chest pain or discomfort that occurs when your heart muscle does not get enough blood . Men in the test group reported that it was a failure at stopping high blood pressure but it had one beneficial side effect.

Pfizer investigated the side effect and found that the drug had a dramatic effect on men's sexual vigor. That Drug is Viagra, which became one of the most successful failures of all time.