How many times to does it take for you to really "get" a movie?

Sorry if the question itself is a little vague. You know, how many times does it take for you to watch a movie before you understand the message or themes that a movie is portraying? I mean, some movies out there have serious smack-you-in-the-face-see-what-we-did-there ideas presented, and I can usually pick up on the themes after one viewing. But others, like Inglourious Basterds, I had to watch about 50 times to really understand what, if any, themes were present in the movie. And I could be totally wrong, to boot.

But enough about me…