If you're laying down the bricks for a house, there really aren't any cheap tricks or shortcuts. Building two houses takes twice as many bricks as building a single house, and so on. We could say that brick usage scales linearly with house construction. This is a bit of a bummer for bricklaying enthusiasts, but on the other hand, a single brick out of place is probably not going to bring your roof crashing down.
Software is different. Often, the distinction between processing 100 files and 1,000 files is minimal at best. This ability to scale effortlessly is often the best thing about software, but the same non-linearity is also the price we pay for power. A single subtle programming error can cause millions of dollars' worth of damage and bring massive systems to a grinding halt.
Overall, I think this is what makes software interesting and exciting to work with, but I can understand how it can pose a steep challenge once things like reliability and security become major concerns. The way I see it, much of research and development into better programming languages and tools has been to see how we can systematically mitigate these kinds of propagating errors and make our systems more robust to mistakes.