Sometimes, what is very close to us, becomes 'invisible' to us- like our face, our eyes. You need another's help to take a speck from your eyes. Same way, for many of us, even though stammering has been very close to us- and yet, it has been so mysterious. We dont really understand much about it. Therefore, using analogies or a similar phenomena sometime works. Addiction is one such health issue. For a long time, society beleived that it is a habit, a bad habit- or it is some kind of mental quirk ("Only people with low self esteem or poor will power indulge in addictions"). Because of such assumptions, there was (still is) strong stigma and shame involved. Families often believe that by criticizing and "being firm" s/he will give up addiction (which could be anything from over-eating, alcohol, drugs, tranquillizers etc.). Research in Neurosciences is revealing deeper facts now. Read this article and compare with stammering scenario..