The longer I stutter the more I think that it is a mix of lack of confidence and too many bad habits. The chimp paradox is a book that talks about the conscious, subconscious and autopilot. I think it is an interesting book when you think about stuttering and worth a read. I feel I have learned a lot of stuttering behaviours and automatically slip into them making myself less fluent. With confidence, if I practice a talk ten times then it goes well, if I don't then I start to trip up and it all goes a bit wonky. At home I am very confident and stutter less. Elsewhere I am less sure and stuttering more.