I see this like walking into a room where there is an unbuilt puzzle on a table and I am introduced to the process at a later stage:
I don't like when I am busy with an area and then find that the puzzle pieces for that area are literally missing. Like for example: if a library has been introduced, and I am expected to enhance the area 'quickfix' using THAT library and am given a set period of time. So turns out the library has been discontinued...
The problem is not re-doing the area, or finding another library that does the same thing. The problem in this case would be time, I suppose