What do you call it when you come back from a retreat? — an attack?
Well, technically, I wasn’t on a retreat. I was at the 2010 Academy of Missional Preaching (Southwest). But it was held at the Serra Retreat Center in Malibu, and there were retreat-ish aspects to it. If you needed to work on a sermon, you could go sit in a garden like the one above and think about what you were trying to say. It was a pretty harsh existence, but we must all be prepared to sacrifice for the Kingdom. 
Of course, it was not only about preaching, it was about missional preaching. (Missional is the idea that the church exists as an instrument used in God’s mission to the world. See John 20:21, Acts 1:8, etc.) In addition to preaching, we also got to hear various speakers including John Dally (Choosing the Kingdom) and Darrell Guder (Missional Church).