I can't find the words to explain it better, so I will give an example: Lets say that in a lucid dream there is a room with buttons that represent each emotion and I truly convince myself that if I press it I will get that emotion. When I press the Anger Button, I suddenly feel angry out of nowhere, when I press the Happiness Button I feel happy out of nowhere. I remind you that this was an example and I did not actually experience this. So, would such thing be possible in a lucid dream?