There are two completely different conclusions that I would draw from his facts: 1) Most bugs are in code. But it might not be your code. Your code layers itse

There are two completely different conclusions that I would draw from his facts: 1) Most bugs are in code. But it might not be your code. Your code layers itself on top of many other layers of code that are outside of your control. Learning to deal with that will make a difference in your work. 2) Know how everything works. I am always hocked at people who claim to be web developers who don't even understand how an HTTP request/response works, much less what your browser does with the results. It is one of my interview questions for tech folk - I ask them to explain to me exactly what happens on the server when a browser sends it a request. Few people can give much detail here. Most can only give a generic explanation of the actions taken, if that.