The Universe does not know or care whether the vibration that you're offering is in response to something you are living right now, and observing, or in response to something you are imagining. In either case, the Universe accepts it as your point of attraction and matches it.
The work of Abraham essentially says that we attract into our lives what we are thinking about, and our emotions are even more important -- so it is important to maintain feelings of well-being and thoughts of well-being -- according to these teachings. Even if these teaching are not true, we benefit from thinking positively and maintaining emotional well being. Well-being supports our health emotionally, physically, and spiritually.