After the space shuttle Columbia disaster in 2003, NASA worked exhaustively to solve the issue before re-launching the program, and they believed they solved every possible issue before flying Discovery in 2005. Problem is, they didn’t solve the cause:
What you probably don’t know is that a side note in a final briefing before Discovery’s flight pointed out that the large chunk of foam that brought down Columbia could not have been liberated from an internal installation defect. Hmm. After 26 months of work, nobody knew how to address that little statement. Of course we had fixed everything. What else could there be? What else could we do? We were exhausted with study, test, redesign. We decided to fly.
When Discovery flew in July 2005, despite all of the work NASA’s team put in to make sure what brought down Columbia never happened again, the same issue recurred: foam came off the fuel tank during launch and possibly struck Discovery’s wing.
Luckily, either the foam missed the wing or struck it with such a glancing blow that no damage was done to Discovery’s heat shield.
This is a story of working tirelessly to solve a problem, but missing the problem’s cause, and therefore not solving it. It’s a story we’re all probably familiar with in our own work, but this one involved people’s lives. Work isn’t useful when it’s misdirected. Learn it, live it.