PDF vs Word compatibility

It's strange but I just got off the phone with the third person in as many weeks who couldn't open a PDF file from me but Word documents were ok. What kind of strange world is it when Word documents are more compatible than Portable Document Format files are?!?

Am I missing something? Are corporate IT people preventing PDF readers from being installed? When one lives in a MacOS X world PDFs just work everywhere, I guess I've been spoilt.