Something Word does, for better or worse, is encourage lazy behaviour which produces hard to maintain documents. This is fine if you have a one page letter or a one off simple text document. However if you are trying to manage something sizeable then it can be hellish to make document wide changes. It's like the php of document editors, easy to start and forgiving, but hard to do correctly.

Compare this to, for example, in design, and you'll see why Word is hated by the print industry.