There are a number of different theories on cold calling. Very rarely will you meet someone who enjoys cold calling but if it works 1 time out of 10, then you are bound to try it again. One theory on cold calling is that it is a great tool to reach into new markets where you do not have any connections. If you do not know people in a specific neighborhood, then one of the only ways to reach out to them is through a cold call.
Another theory on cold calling is that if you call 10 people and have 1 success then you have turned off 9 people to your organization. Most people do not enjoy receiving cold calls much more than we enjoy giving them. As a result, a cold call can leave a bad impression on the individuals who were not receptive.