One of the big differences between computers and human brains is that computers are willing to sit there patiently while you define the terms that you want to use later. But humans won't understand what you're talking about unless you motivate it first. Humans don't want to have to decode something, they just want to read it in order and understand it. For humans, you have to provide the big picture and then fill in the details. With computer programs, you start at the top and work your way to the bottom, with full details throughout. A computer doesn't care if your variable names are meaningful. A human brain understands things much better if you can paint a vivid picture in their mind by telling a story, even if it's just a fragment of a story, because our brains have evolved to understand stories.
Joel Spolsky: Joel on Software