Things in Movies that make you go WOW! or No Way!

So last night while packing for my trip, I was watching Back to the Future.

At one point I got tired of running up and down the stairs for clothes and toiletries and such, so I plopped down just as Doc Brown was tightening the wire on the ladder and the cop walks by and tries to look under the tarp covering the DeLorean.
Just after that, Marty slides the note he'd written (the one marked 'do not read til 1985') into Doc's jacket, and in the background you see Doc -bribing- the cop!

I was like, OMG!

And then I remembered all the times I'd watched The Love Bug (have since I was, ~3, but very much recently up til Fully Loaded's release).
There's a point after the first leg of the Eldorado where Jim, Tennesee, and Carol are working on Herbie. Thorndyke appears and insults and kicks Herbie and insults Jim, and Herbie starts and chases after Thorndyke, who jumps over a fence. Mr. Wu makes a comment about Herbie having "the strength of forty horses."
Well, it wasn't until last month? (very recently in any case) I realized what he meant - the 1963 Bug had only a 40hp engine.

So, my point is... Is there anything you've gone through a movie and watched and seen something that you didn't understand the first time, and the second (or nine hundredth) makes you go "AH HAH! I get it now!" ?