I'm so shocked and relieved that this is a thing, I've been doing it for about 20 years or as far as I can remember. I'll listen to music and pace in a room, for hours on end between for 1-6 hours straight. I get so caught in these thoughts I go through them over and over, repeating the song sometimes. I feel so involved sometimes I'm crying hysterically on the floor, or laughing and dancing depending on the thoughts. When I've not been able to do it I feel stressed and anxious. Its like whatever emotion I feel in real life I have to go and do my thing..plug headphones in and shut the blinds, lights off and im away. When I was a teenager it got in the way alot as I'd rather do that then go out and socialise. Thing is it does make me content in a way. It does feel like im socialising.