Security is not a trite one.
Security, security, security. You may have been defeaning with your boss' emphasis on it. Why do many argue that security is important?
Most people think that it just increases cost. That's right if your application or service is only for your company. But how about commercial product? Actually a bunch of companies don't think of the next while developing applications. They don't think maintenance, backup, risk of rebuked by customers, and even SECURITY. They just focus on what to make or what to develop.
What is the value of security? It resembles health insurance. If you're healthy, it would not be needed. Otherwise, the cost would be serious. By a statistics, the cost for maintaining or restoring from latter problems is about three times more than the cost for developing. Considering security issue is one of the most significant matters in desigining process I think.