Explaining it so they understand, ridiculous parallels edition

I had a client with Windows BSOD problems, one of those who insists on detailed explanations for why something isn't working even though he doesn't understand. The hard drive in question had a whole bunch of bad sectors. My go-to explanation in the past has gone something like this:

"You know how kindergarten classrooms have little 1'x1' cubbies for the kids' stuff? Well, imagine that one kid's cubby is filled with concrete. All the other kids can still get their things, but Concrete-Cubby-Kid can't get anything in or out.

"As long as Concrete-Cubby-Kid doesn't need anything from his cubby, you're ok. As soon as that kid wants to get something, he throws a tantrum because he can't, which wrecks everyone else's day.

"Your OS isn't working properly because it needs something in that concrete-filled cubby, and can't get it."

Amazingly enough, everyone understands! It's worked for explaining defragmentation too: "If you put everything in one cubby, you can take it all out at once instead of going to 10 different cubbies."

Who else has some ridiculous parallel-paradigm explanations?