There is an expectation of top to bottom, in-order execution from a notebook. The point of it being a "notebook" is that it's like a scientists journal where th

There is an expectation of top to bottom, in-order execution from a notebook. The point of it being a "notebook" is that it's like a scientists journal where they write the equations, solve them, write notes on the solution, and proceed from there. The execution order is implied from the skeuomorphism of the notebook form. This is why the notebook paradigm is not generally suitable for software development. They're well suited to using code to get answers from data, for learning, and for trying things out. But you wouldn't use them for building your next SaaS product (unless that product is a site for hosting notebooks..., or you're making Mathematica).