API nightmares: what's your story?

vaspersthegrate writes: While I gather my thoughts and references, relative to API design, testing, and promotions, let me ask you a question. Feel free to respond. What API disasters have you experienced? Tell me about your API nightmares. APIs that changed, didn't work, had bad documentation, poor presentation format, were hard to work with, had a buggy core product, had lousy developer support, etc. Help me compile my research into API Marketing, and ride my coattails into oblivion! Actual research findings, URLs, and citations coming soon. Stay tuned.