At the beginning of Parshas Mikeitz, Paroh asks his advisors to help interperet his dreams, but nobody could, until the Sar HaMashkim says he should call on Yosef for help.
The Gemara in Brachos 55b says, though, all dreams follow the mouth, and one dream could be interpreted 24 different ways which are all correct. So why couldn't the advisors come up with an answer (which, by the way, they did - see Rashi to Bereishis 41:8) which would automatically be correct? Why did Paroh need someone else to interpret them?