cimorene

I really can't see any plausible reason for Ari's strong German accent. I mean, he's in his thirties so it's possible that his dad was born in the 40s and came from Germany and that German was his native language, but Ari's native language should still be either Arabic or Hebrew (or he could be a true bilingual). Even assuming German was spoken at home, Arabic or Hebrew should be the accent since it would be the language of his education all the way up to med school.

And according to IMDb, Ziva's played by a South American. How hard can it honestly be? Maybe not actual Israelis, but how about some jews or at least a British accent, so we could pretend they were just talented? And for that matter, Michael Weatherly's conspicuous un-Italianness: why the Italian name then? Surely it wasn't necessary?

Not to say that these are the only things that stand out, but given a choice language is always what we fixate on in this household as a pet peeve. That, and Gibbs's haircut.