A telecom bill landed on my desk the size of a phone book. $20,000 for the month. Everyone had been paying it for years because that's just what it cost.
I asked why. It was almost all inbound 800-number calls - customers who couldn't figure out how to use what they'd bought. So we made setup videos for every product. Call time dropped 90%. Then I renegotiated the contract to a flat $4,000 a month.
$16,000 a month back to the bottom line. $192,000 a year. All because one person asked why the bill was so high instead of just paying it.
This is the scoreboard. Post your wins here - the leak you found, the cost you killed, the number you moved. Big or small. We celebrate the people who ask why.