Closing Word documents

I can never understand why programmers continually fix things that aren't broken. Microsoft continually changes bits of the Office interface, so that things go missing or don't work the way they did before. A case in point: In previous versions of Word, if you had only one document open and clicked on the X at upper right to close the document, the program remained loaded. In Word 2007, if you do the same, the entire program closes. I have watched frustrated users do this time and again. The simplest answer is to close a document using the keyboard command Ctrl-W (a shortcut which works with many applications, by the way, including web browser tabs). But why should you have to?