Be like the reed... blowing in the wind. It's not a haiku, Jesse is talking about Rule Three -- rolling with the punches. Life happens, and unexpected things are going to pop up that could break the budget. When you roll with the punches however, you check the budget, find the money for the unexpected expense in another category, and fund the expense by moving money from that category.
The key here is that you check the budget and find the money first! You don't simply spend the money and try to figure it out later.
