Microsoft Word and I have an interesting history. For the longest time if at all possible I avoided Word, preferring to use one of the "splashier" applications available via Microsoft Office. I had to make a poster? Publisher. I have to set up a series of pictures and captions? Powerpoint. As far as I was concerned Word was only necessary in the case of having to write a paper for a class, otherwise I considered it to be relatively useless.
Well, things changed. I took a course on Computer Applications during undergrad and as it turns out, the first program we explored was Word. I learned a great deal about some of the capabilities that Word has even as a designing program for flyers, menus, and other items that I would have considered best created in Publisher or Photoshop. As it turns out, there were still plenty of features Word had to offer that I never even heard about in that college course. As for the different features that Word has to offer, I consider the citation tool, the comment tool, and the captions tool as the most effective for the work I have done over my many hours of using Word.
As a history major in undergrad, citations not only had to be completed for every source I used, but also had to be inserted in the document as footnotes (as per the Chicago Manual of Style). Unless it was a repeated source and I could just throw an "ibid." into my citation, it was initially a pain to insert a footnote, write out an entire citation, mark the page number, return to my thoughts in the body of text, and then repeat the process for the other 20 or so sources I'd have over 10-15 pages of text (and do this entire process several times a semester!). With the citation tool I could "pre-load" the citation before I even included it into the body of my work so when the time came to include it I could just add a footnote, click on the source in question and move on. This process likely saved me hours of time over the years.
The comment tool was useful for peer editing and having other evaluate my work before handing it in. I first discovered this tool my junior year when one of my professors used comments on a Harvard outline for the class's main paper (she crushed it by the way). Once I learned the finer points of the feature I found it most effective to get ideas from a friend whose opinion I valued highly as both a historian and a writer. Since she had graduated earlier, getting a chance to have her read my work my senior year was complicated timing-wise, so comments allowed her to say everything she needed to say without having to decipher a long e-mail or make an extended phone call.
Captions were useful for the aforementioned junior year paper, in which the professor requested we use tables and graphics in our paper to support our points. Since I relied very heavily on a few specific tables, captions allowed me to designate which exact figure(s) I was referencing.
So I have come to learn that as a document producing tool, Word is just as effective as the other programs I once considered to be "splashier." There are some features I don't care for (mail merge is one of them, as I'm incredibly OCD and don't mind the tedious process of doing each letter individually), but at this time, especially working in a school and creating worksheets, I consider Word to be one of the more valuable programs I use.