Once upon a time there was a scientist who wished to learn about the cause of complete happiness. Somehow he got his hands on a machine which could bring back people from the future. He traced the brain signatures of a number of candidates before selecting one whose aura had the radiance similar to his findings. The machine communicated to the subject in a unique fashion: it offered them the choice of going back in time while they dreamt of things that could have been.
He narrowed it down to a subject who showed exemplary satisfaction with his life. The fact that the subject refused the chance to come back to make things right reinforced the scientist’s faith as to the appropriateness of his choice. After a lot of coaxing, he finally got him to visit his past: the scientist’s present.