Last week I was trying to explain why for so many years word processing software like Microsoft Word, Open Office and even Apple's Pages annoy me so much.
There are two basic ways you can approach desktop publishing. The first is to augment to your base "text flow" with additional semantics and maybe some direction about how it should be rendered on page, and then you let whatever rendering software you use render it the best way it can for the target page's dimensions. This is what I called the "descriptive" approach, and is the approach used by TeX, DocBook, XSL-FO and HTML.
The second approach is one in which text flow is done in text boxes you prepare in advance. Actually, you draw every small detail of the page and where the text should go. If effect, you control how many pages exist in the output. This is the traditional approach for newspapers and magazines. I called that "prescriptive". Software like Quark XPress and Adobe InDesign do exactly that.
The problem with Microsoft Word and the likes is that they attempt to be right in the middle of descriptive and prescriptive. On large documents, you can see it computing the total number of pages, as if it was rendered on the fly. Opening a Word document from a machine that has different fonts causes the document to be re-rendered, causing minute adjustments to break. And there are lots of such adjustments, because its "rendering" aspect exists, but is quite limited. You can "describe" many things in the document using styles so that it can get picked up in a table of contents (that you have to manually re-render from time to time), but beyond that most people like being in control of the spacing and formatting not through paragraph styles, but by inserting blank lines like you would do on a typewritter. So, yeah, Word is just a glorified, messy electronic form of a typewritter, with the pretence of being both descriptive like HTML and prescriptive like InDesign, but failing at both. It still has its use, and covers the needs of 90% of users out there, but personally for any considerable work I'd rather fall back to HTML than touching Word, Pages and so on.