Since I'm working in a large organization I have come to realize that the amount of documentation in many projects is huge - often so large that essential key information is masked away, or right out FUBARed.
It's also not uncommon that the customer requirements are "interpreted" by people with no technical knowledge whatsoever and they have a tendency to eradicate information that they think is "too technical", or information that they think drives unnecessary cost. Some people also have a tendency to rename things to a semantic that is to common people fuzzy. Even obfuscation occurs. At the same time documents are filled with a large number of pages listing old or discarded alternatives.