I can’t generally advise spending years on peyote or full-time isolation in a cave. The most practical examples of manipulating time perception come from the common observation that the more we think about time, the slower it goes. In his treatise The Principles of Psychology, William James wrote, “A day full of excitement, with no pause, is said to pass ’ere we know it.’ On the contrary, a day full of waiting, of unsatisfied desire for change, will seem a small eternity.”