There was no Viagra in 1918, but there were plenty of goats.
At the time, the alleged sexual prowess of goats enjoyed legendary status. So it was that Kansas physician John R. Brinkley made a small fortune surgically implanting goat testicles in men seeking to enhance or restore their own virility.
Never mind that the procedure failed to deliver the promised benefit; that Brinkley was a medical school dropout who bought a diploma for $100; or that most of his patients died during or shortly after surgery. A steady supply of men handed over their cash to Brinkley's scruples, and their privates to his scalpel.
I hope you agree with me that the decision to undergo Brinkley's procedure was irrational. The risks of infection, mutilation, sterility, and death were clear... yet otherwise presumably intelligent men convinced themselves to go ahead with implantation anyway.
Of course, you already know the answer. People who really, really want to believe, will believe—regardless of where the evidence points. Brinkley's patients really, really wanted the promised benefit, so they embraced his trumped-up "success stories," and disqualified the negative outcomes.