Why test?

Patriot Missile Defense System, 1991

The U.S. Patriot missile defense system is a scaled-back version of the strategic defense iniative ("Star Wars") program proposed by President Ronald Reagan. It was first put to use in the Gulf War as a defense for Iraqui Scud missiles. Although there were many news stories touting the success of the system, it did fail to defend against several missiles, including on that killed 28 U.S. soldiers in Dhahran, Saudi Arabia. Analysis found that a software bug was the problem. A small timing error in the system's clock accumulated to the point that after 14 hours, the tracking system was no longer accurate. In the Dhahran attac, the system had been operating for more than 100 hours.

Let's home our mind to that disaster. Being smart doesn't mean we need to eliminate software completely and get back to manual. Allow me to coined the idea to any situation. Assuming you have a medical software that repeateldy create a calculation error or even a simple color labeling error. Do you think it's safe or profitable to use your software? If you produced that buggy software, are you happy to have your name on it? If you think testing only exists for marketing purposes to add flavor to the product then don't be surprise that you end up back in the corner in the future. People will never use your software because they are not happy with it, worst, they will have a campaign not to use your product and apparently you lost your company.