The numbers game

If I have one bone to pick with the personal development industry, it's numbers. 7 steps, 14 ways, 21 ideas. Why is this number or that number the perfect set for that particular thought? Is it marketing? Do the writers have a sixth sense, knowing that it's not six or eight, but seven? I see these lists, and my first instinct is to roll my eyes. Then I read down through each point. Then, I pick the ones I can work with most effectively. When I see these, I'm looking for what I can apply to my own life. That's the hardest thing--the execution of the strategy. Lists are easy. The application, ahh, now there's the rub.