Originally Posted by RiCharlie

If you have spent some time in Japan you know that the term Datsun is very offensive. In one Japanese dialect "san" or "sun" means car and "Dat" means "crazy person" This car company started marketing cars shortly after WW2 when feelings against the US were running high. They named the car "Datsun" or "crazy persons car" as a secret slight against Americans.
Later when feelings improved they changed the name to Nissan..meaning "intelligent persons car" Nis being the Japanese word for intelligent.

To this day this has been a closely guarded secret in Japan known by all Japanese but hidden from the outside world..

So if you use the word Datsun when referring to someones car..better hope that person is not Japanese!

Now I am sure they will all deny this but dont say you were not warned!