Shaun of the Dead was never very funny to me...
I've seen it twice, and I'm so bored that I zone out toward the end both times.

But I think the BBC Office is hilarious... so, I don't know...

That kind of dry humor really fits in that office setting...and most of those lines are so damn quippy. To the point that if you don't pick up the slang you'll be lost on most of the jokes...

Also, there's no laugh track, so maybe you just don't know when you missed the joke...