Being able to improvise is the basis for creating all characters and situations, for everything to do with performing, really. And it's good therapy as well.
It wasn't all frustration. I've had a lot of good times with Ferrari as well.
Well, I've learned something from Michael Robison just about maximizing your shots. For example, if I'm shooting a scene and someone's driving at the wheel, you could steal an insert in the same shot.