People build castles virtual and real. The thing is that the foundation is mostly non-existed or virtual(the blue figure in the lower right corner and the open space between it and the gray figure in the lower left corner). They take the facts(the gray figure in the lower left corner) and their dreams (the blue figure in the lower right figure) and span them with predictions, feelings and hopes. The newly built layer is used as a foundation for the next layer. Sometimes this method works, sometimes it does not. The main thing is when it does not, you should just start over.