As soon as I accepted that the whole world works in ratios, that’s when it became easier. Knowing that success happens in ratios allowed me to go ahead and send that email, without worrying about not getting a response, about ‘failing’.
In sales, this is usually phrased "every no gets you closer to a yes". Joel gives some examples of this fundamentally important rule, but the key is, simply, that everything you do will have a certain success rate, and part of your job as a founder is to figure out that success rate, and then figure out if it's high enough to enable you to run the business successfully.
That you will encounter failures is a certainty. In some parts of the business, the failure rate will hopefully be very low (e.g. keeping existing clients happy). In other parts, it will probably be very high (e.g. sales). That's part of the job.