When we let the autopilot take over our lives, we allow the way we perceive events to sometimes not be the most favourable. Our whole internal system is built for survival. Everything that is negative automatically enters our immediate perception. It is as if we had a lens that filters everything we perceive. This mechanism was repeated so many times that it consolidated these neurological pathways. That is why it has entered the autopilot system.
Our well-being is closely linked to what we pay attention to. If we pay more attention to negative things those are the experiences that will be stored in our memory. It is therefore important to store positive memories. It doesn't mean that you don't pay attention to bad experiences. But we don't need them to dominate our lives.