Happens from the bottom to the top. The problem with it happening at the lower levels, is that this is where the foundation is started and like a house, if the foundation is not there the house crumbles no matter how much was done after.
You know, i've been using that same analogy for years now, and I think it fits so well. I used it to describe the Green Breaking process to my clients though. What I'd say:
"I'm building the foundation for your horse. If you rush the foundation your house -will- collapse. Regardless of the expense you put into the supplies or the time you put into building.. a house CANNOT stand on a poor foundation."
I've lengthened mine out a bit more since then for clients who didn't understand my first analogy.
I say something along the lines of: "Right now, pretend I am building your house. I know you are REALLY excited about the house being built, and moving in to your new digs, but you need to understand that I must first start with building the foundation. This can happen relatively quickly if the house site has already been cleared and leveled.. but it could take a while if you expect me to clear your lot and level your ground. Once the foundation is down and set we can go ahead and get you another step closer to moving in."
Then i'd give the translation: "I know you're really excited about having your horse ready for the show ring, and I can help you make that happen, but first I have to Green Break them and get them used to the saddle. This process can go quickly if the horse is of sound mind, you have worked extensively with the horse to gain respect, set rules, etc.. or this will take a while if your horse has never been haltered before. Once the Green Breaking is through, we can go ahead and work on starting your horse's career."
Or something along those lines.
Goodness i'm wordy!
Spyder, howcome i've never seen pictures of you riding? :p *grabby hands*