The word "hallucination" has a bad rap. There are lots of negative connotations to the word.
I heard a brilliant explanation that takes the mystery and fear out of the concept of hallucination. David Snyder, a leading instructor in the fields of NLP and hypnotherapy, states that hallucination is simply a designation for whether an experience is generated internally (hallucination) or externally.
Internally generated experiences can include emotions, thoughts, and bio-responses. Ever slow your breathing on purpose? Ever think get all mushy thinking about your significant other when they are away? Ever relive a childhood memory? Ever cry at a movie?
Those are all INTERNAL experiences- technically, hallucinations!
Ever lose your keys only to have someone else point them out right under your nose? That is a negative hallucination. Your own mind convinced you the keys weren't there and so ... for you... they weren't!
Positive and negative hallucinations are normal and natural. All it means is our minds are creative, powerful, and amazing. So free yourself and hallucinate to your heart's content. I regularly take mini-mind vacations to the Gulf of Mexico, where the water's as warm as a bath, the beach glitters white, the gentle shush shush of the waves comforts, and my lovely wife is by my side!