One study found that people who just thought about watching their favorite movie actually raised their endorphin levels by 27 percent.
Daniel KahnemanDoubting what you see is a very odd experience. And doubting what you remember is a little less odd than doubting what you see. But it's also a pretty odd experience, because some memories come with a very compelling sense of truth about them, and that happens to be the case even for memories that are not true.
Daniel Kahneman