Yes, But - No, And

I was listening to the Writing Excuses Podcast the other day in my car, when I came across this fantastic nugget of advice about how to do chapters/scenes.  How do you move forward from one chapter to the next?  You need to know how to develop the connective tissue and keep driving the story forward.  This simple trick will take you a long way to developing a story that has momentum.  You simply ask a question, is the protagonist going to accomplish his/her goal in this chapter?  You have two answers obviously, Yes or No.  The trick is thus: Yes, But and No, And.  Every chapter/scene needs to have a reason to exist other than you thought up some really cool world building stuff that you want to show off.  The Yes, but will allow you to finish minor story arcs but keep propelling the story forward.  For example, your group needs to cross a bridge in this chapter.  Will they make it across?  Yes, but on the other side they encounter a group of ruffians.