Whenever something is going to happen, our brain does a quick calculation of probabilities and of course imagines the more favorable or at least more common results. In order to explain this phenomenon clearly I’ll use the theme “home” as a metaphor and I’ll relate it to the musical context.
Imagine, for example, if someone would knock on the door. You cannot imagine it is going to be a wolf, especially because you know you are not in the context of a fairy tale. You can imagine it is going to be a postman, especially if you expect a letter and that is the time when the postman makes his deliveries. Or you might imagine it is someone that you invited for that time.
If you have no idea about who is knocking at your door, your mind will imagine the more strange things, but still more likely to happen. Your mind will rationally discard the idea that you have an extraterrestrial visitor out there, but it could probably imagine you could deal with a common criminal: the unknown requires us to think protectively towards us.