We figured this out at the first couple of PLoP conferences--writing patterns, reading each others' patterns, and discussing what seemed to work best. Ken Auer has documented this well in "Therefore, BOOM!" It's already described in Sun's Java Patterns Community, so I'll let you read about it there.
Simply put, as a pattern author, to the extent you can write your document to embody this "BOOM!" quality, the better your pattern is. I believe that it makes your pattern better in at least two respects; it makes your pattern explanation:
- More interesting -- If readers are going to have to read through dozens of patterns, if you can make the writing a little more entertaining and a little less dry, the easier it will be for those readers.
- More memorable -- The "BOOM!" quality provokes an emotional response in the reader that makes the pattern reading experience much more significant than it would be at a purely intellectual level. The reader will internalize your pattern better and remember it more easily.
"BOOM!" is one of, if not the, major reasons why well-written patterns work so much better than just using standard prose. A pattern is not an experience report, and it's not an account of a cleaver trick; it's a mind-meld from an expert to a novice of what works well. It's a best practice that you know not just in your head, but in your heart and your gut as well. "BOOM!" gets that gut feeling across in a way that words alone cannot.
Think about a pattern you've read that really resonated with you, where you knew as soon as you read it that the author knew exactly what he was talking about. (And if you've never had this experience, you need to read more and better patterns.) Remember how you felt (not what you thought, but how you felt) when you read that pattern? That's "BOOM!"