This evening it happened to me to read this quite interesting article about why software is so hard to write. In the article, if you don't care or do not want to read it, the blogger reports the decision of a friend of his quitting his (probably highly paid) job as software developer because he got tired of it. The motivation he (the one who quit) suggested are that software is complex to build and is the only large-scale human artifact that is mostly built by hand. Hand-made stuff, he argues, is more fragile and error prone that machine-made stuff. He also points out that good software developers do not agree on the right way to do things, etc. Eventually, he arguments that in civil engineering architects (or engineers) design stuff, politicians and administrators regulate it and carpenters build it. That thing is not possible with software.
So I have to say that: I'M FUCKING TIRED OF PEOPLE COMPARING BUILDING SOFTWARE TO BUILDING HOUSES. It is not the same thing. Moreover, I believe that comparisons with other forms of engineering has been detrimental for software development and lots of wrong practices and costly mistakes came from this illusion. I also think that people who really believe that building software is like building houses should be building other stuff. Neither software or houses (not houses I'm going to live in). Am I saying Rational F*cking Unified Process?
Humans have been building houses and bridges for millennia (yeah) and software since 50 years. It is quite natural that techniques have been developed. Software engineering is young. Really. So please, have patience. We will surely agree on the principle. That will happen earlier if people realize that no matter the process, unskilled developers are not going to build a working and maintainable piece of software.
Regarding the objection of software development being too manual, last time I checked, gcc and javac are exactly machine building software, not a bunch of underpaid third world workers. So, we do have machines building software. Compilers, build systems... testing infrastructures. We have lots of machines that help to build software, much in the same way that we use machines to build other things. We do not use machines to design most non trivial stuff.
And we continuously create new kind of machines doing stuff for us. Moreover, in the last 50 years we have been rising the abstraction level: since CPUs basically compute the same stuff, it means that we have more "machines" at work. People do not write opcodes. We write Python (Lisp? Clojure? Ruby?) code that is compiled and/or interpreted by a machine that runs on a machine called operating system that offers uses the services provided by a machine called kernel that uses relatively high-level services provided by the hardware. I don't tell the computer to write a 0 in some position of the hard disk!
Of course, we don't have machines that convert pointed-haired-boss-level babbling and unclear requirements to executable software. In other words, software developers are not skilled in divination. Perhaps haruspicy  or augury should be added to CS curricula. The problem is people do not even know exactly what they want. The best we can do is to keep them involved in the development process and use continuos feedback to deliver the product they expect.
"Name one other thing in the world, he said, that is used by so many people and which is created entirely by hand"
Well, many things come to my mind. Books. Laws. Theorems. You don't have machine writing books (well, in fact IA tried to build machines performing some limited "artistic" tasks, with mixed results -- the more constrained the piece of art, the better the chances --). I do not think we have machines writing laws. Human have been creating laws for millennia. We *wrote* them down. And still, there is not consensus on what is right. Laws are bugged and there are people exploiting bugs in them (and that is not even closely illegal: it is the highly paid profession of the lawyer). We don't have nor want machines writing laws for us. Experts do not agree in what is a right law. Laws are continuously changed, modified, patched, deployed (in Italy we have the concept of "decreto attuativo" which I'm not even sure it has a clear translation in English -- the idea is that the law is so vague that you need some "lower level" laws to actually explain how the law should be implemented). Laws are unjust. And nobody fucking complains that the Romans could build bridges lasting millennia (I could have a roman bridge right under my feet right now) and we can't have unambiguous laws. Well, romans were pretty good to write laws as well...
So essentially the point is that some people think that software should be like houses, because it is a product. I think that software should be like poetry, because it is an idea.
 The problem is that if you believe write requirements based on sheep guts then maybe you should start the noble profession of PHB.
 s/sheep guts/birds flight/