cool things with wheels since 2006
Maybe the pawn shop loses them too.
There may be another explanation; 10mm is one of the most popular nut/bolt sizes on Japanese cars (maybe European too) - especially older ones. (Sort of akin to 9/16 and 1/2 inch sizes on GM cars/trucks from the 50's/60's etc.) I would imagine that every DIY car person needs one to even work on the simplest of things, so they sell a lot more of them, than other sizes. Eg, I needed mine to change the battery on my 2002 Lexus ES - both battery connections and the battery hold-down clamp were 10mm.
that is the reason, but it lacks humor and ridiculous over thought explanations. I'd rather use a Rube Goldberg machine than just flip a switch, and often my humor gets inserted to craft a phrase that over explains a situation, rather than just say something briefly. Wheres The Fun?