TL;DR Watch THIS.
Jeff Atwood at Coding Horror has made a couple of really interesting blog posts about the true interactivity and feedback loop delay. Basically, the longer it takes to get feedback about what you are doing, the worse.
In What you can’t see you can’t get, about document authoring, Jeff mentions the gripes of working with WYSIWYG editors because of hidden format tags or invisible whitespaces. The current solution to this is using LaTeX or markup languages, where you can focus on content and intermix formatting tags whenever is necessary. I deeply believe this is a way better approach. BUT there is a long feedback loop between what you are writing and the actual document being produced. Usually, you write some content, save the document, compile (a couple of times if necessary), and then, if everything goes according to plan, you can see your document in a pdf/dvi viewer. When I was an undergrad student I remember my friends and I learning LaTeX. Everybody knew that, if you took to long to compile your document, you had to pray to the LaTeX gods for it to compile correctly, otherwise you were trap in a bug hunting quest for the next half an hour. Eventually, for any non-trivial document, you compile frequently and split your screen in two, in one side you have your text editor, and in the other your document viewer, to be able to preview your work.
What about being able to switch between the two easily, while keeping track of where each part of the document came from? Enter Gliimpse project.
But, in Visualizing code to fail faster, we enter the world of Bret Victor and his principle: Help ideas flourish by giving their authors tools with immediate feedback. He argues that, by allowing people to see what they are doing in the computer right away, instead of having to imagine it until the computer is ready to display the results, you strength ideas and enable more creativity and better understanding. At first it didn’t felt attracted to the concept, but after watching his talk at CUSEC I’m convinced.
Make some time to watch the video. It’s AWESOME, really. I mean it.