The Fast Test and Slow Test

I want to go back for one second to something you mentioned earlier which was again this idea of the fast test and slow test. There are things that you need to do and act on right away and other things you can take another second and think through. When did you start sort of teasing out the difference between those things and how did you learn that? You know I specifically learned this idea from Matt Keefer who's a great great guy.