I don't know whats more embarrassing - that he rode completey stark naked through Sydney on his 30th birthday or that I know that.
We rolled a lot when cast weren't aware, allowing for more spontaneous (and funny) reactions. And don't go trying to scare your Aunt through the sunroof. That demanded some pretty nifty filmmaking. With a platform moving in tandem with the sunroof, carrying his weight from the hips down, our hero's reaction was the first take (yes, we shot the rehearsal) where he's genuinely thinking "WTF?"