This story has been around for 80-100 years and has been re-told in various forms. The author is unknown.
The Engine Mechanic
A giant ship engine failed. The ship's owners hired one expert after another, but none of them could figure out how to fix the engine. The owners were losing money every day as their ship sat idle.
Eventually, they brought in an old timer who had been fixing ships since he was a young man. He carried a large bag of tools with him, and when he arrived he immediately went to work, inspecting the engine from top to bottom.
After looking things over, the old man reached into his bag, pulled out a hammer and reached down and tapped on a small place on the engine. Instantly, the engine sprang back to life. He carefully put his hammer away. The engine was fixed!
A week later, the owners received a bill from the old man for ten thousand
dollars.
"What?!" the owners exclaimed. "He hardly did anything!"
So they wrote the old man a note saying, "Please send us an itemized bill."
The man sent a bill that read:
Tapping with hammer....................... $ 2.00
Knowing where to tap.......................... $ 9,998.00
The moral of the story is that, while effort is important, having the experience to know where to put that effort makes all the difference.