OOXML; Office Open XML. Even the name is false as it clearly isn’t ‘open’ in the sense of non-discriminatory, particularly against GPLed implementations. It’s not at all clear whether a GPL implementation of OOXML can be done.
Then there’s the specification itself. 6,000 pages at the first round, growing to something like 8,000 after the BRM. The sheer number of technical errors, failure to incorporate other ISO standards in the appropriate places, and downright contradictions should have ruled out the specification from becoming a standard. That Microsoft shoved this standard into the ISO Fast Track by getting ECMA to rubber stamp it shows a complete disregard for the standards process. Technical committees the world over agreed that the standard shouldn’t have been fast tracked.