To be an effective salesman it takes a lot more than a good product.  We have all heard of products that sell themselves, however the reality is that even the most easily sold product would not do so unless someone sold it.  For example, if a scientist invented the cure for cancer and it had the side effect of perpetual youth and vitality no one would buy it unless it was marketed right.  Even after the marketing campaign someone is going to have to sell it and even with this wonder drug the sales staff will have to overcome objections.