No one finds the 10mm. Even though it was placed right there, the spot will absolutely not have it. Sure, you can look around that spot, in case it rolled nearby - but it will NOT be there. It won’t make sense, and you will assure yourself that it didn’t just get up and walk away…. BUT DID IT?
Somewhere, in field of unicorns farting skittles there is a mountain of 10mm sockets by a river of tears of guys having to and but yet another replacement 10mm.
It’s further proof we should never go all metric.
There are two kinds of people.
Those who use the Metric system, and
Those who have been to the Moon.