This explains why an emotion like “happiness” can feel like it’s a reaction to external events, rather than generated from within the brain. Even before your brain has finished categorizing a situation as “happiness,” it is also simulating happiness in advance. External perception meets internal construction before you know what’s happening, so it seems like happiness is happening to you when in fact your brain is actively constructing the experience.
This can also become a self-fulfilling prediction: the more you expect happiness to arrive, the more preparations you make for its arrival, and the more likely you are to experience it. Even on a neurological level, you create your own reality.