I am cannibalizing a link from this article that shows why no one should use Microsoft Word attachments. Here is the funnily-aggressive, yet not-uncalled-for (and slightly dated) response of one anonymous user (the link, “Here is a response letter” is at the end of the page:
I’m sorry, but I was unable to read the Microsoft Word document you sent me. Microsoft has been steadily changing the .doc format over the releases of Microsoft Word (4.0, 95, 97, 2000, and now XP). Microsoft has also intentionally refused to release the specification of the .doc format to the community, making Microsoft Word the only application that can reliably open this format. There is the Microsoft Word Viewer application, but it only runs on Microsoft Windows operating systems and does not allow one to edit the document.
The development team that designed the software I choose to use (OpenOffice.org), has tried hard to figure out how the .doc format is created and interpreted, in order to make it available to more people. They believe that all people should be able to exchange information electronically, and .doc is one of the most common formats. So, they tried to make OpenOffice.org, the main competitor to Microsoft’s own Office suite, as compatible as possible with Microsoft’s own formats. But Microsoft did not like this, because it would mean that people that have not bought Microsoft Windows and Microsoft Office would be able to read and write .doc documents.
Unfortunately, it seems that Microsoft is sometimes successful. My non-Microsoft application was unable to open the .doc document you sent me. As a result, we cannot exchange information, until one of the following happens:
 The information intended to be read/processed by me is converted to an open format that people who don’t use Microsoft Windows and Microsoft Office are able to process.
 I purchase and install Microsoft Windows, Microsoft Word, and by deduction all other Microsoft applications necessary to do my work.
Because it will be a cold day in hell before I do the latter, I would suggest we find a different way of exchanging information electronically.
PS: I hope you realize that I have nothing against you as a person. I just can’t use the document you sent me, and I tried to explain why the implicit assumption that I would be able to read it, was mistaken.
PPS: When I tried to open the document you sent to me, my word processor crashed, obviously unable to properly interpret the .doc format. My word processor was handling 4 other documents at the time. Two of them were assignments, and all changes I had not saved were lost. On aggregate, about two hours of my work were lost because the OpenOffice.org developers were unable to overcome the barriers Microsoft put in place, and render the document properly. I believe they are the last to blame for this failure.
PPPS: For further reasons why .doc should not be the format of choice when exchanging information electronically, I invite you to read http://www.gnu.org/philosophy/no-word-attachments.html. It may be long, but it certainly exposes the compromises both you, as the sender, and I, as the receiver, are making by exchanging Microsoft Word documents.
Don’t forget to read the original article I posted above. I intend to use this should a good friend (who can take it) ever send me a MS Office attachment, probably word.
Again, consider the free (as in freedom and in money) no-endless-updates-that-require-you-to-shell-out-more-dough MS-Office-replacing productivity suite LibreOffice – it uses the Open Document format that is an internationally-recognized standard, as opposed to Micro$oft’s proprietary formats and its brazenly-fake standard, OOXML! The lies make me get high blood pressure! But seriously, why buy from a company that cannot even open its own legacy files and still refuses to share the code? Seriously, if you are in the archiving business, stop saving in .doc, .rtf, etc. Micro$oft wants vendor lock-in and then does not even try to support you once you get hooked on it!
Update: Google has a succinct, concise(, and scathing) review of Micro$oft’s fake standard here. A short snippet:
Most of the OOXML implementations are from partners of Microsoft who have contractual agreements to implement OOXML software.