I suspect that traumatic events in people's lives contain the equivalent of hypnotic suggestions.
I knew a girl who was bitten by a dog when she was a child. Any time a dog was in the room, she got nervous - panicky actually - and would perspire, get teary-eyed, etc. Even though the dog presented no actual threat, her mind was convinced she was in danger and had no control over it. Because it's all subconscious. I suspect moments of trauma (unconsciousness, painful experiences) are similar to being under hypnosis and things said in those traumatic moments are also in the subconscious and may act like hypnotic suggestions...?