We just finished our four day Disney World Christmas trip ( ). I noticed with every single ride that we did not fast-pass, the actual wait time was about half what was posted outside. This was the case in all four parks. I feel like they used to exagerate by five or ten minutes, not double! Example "Toy story mania - 50 minutes". No, it was twenty five minutes. We almost didn't go because we were deterred by the wait time (The fast pass return was hours later, and we wanted to fast pass ToT and RRC). So glad we went, it's so much fun!
Anyway, are they deliberately trying to deter people from getting in line, or what? I wouldn't have thought much of it if it happened once, but it was the whole four days we were there.