I really like this TED talk: http://www.ted.com/talks/matt_ridley_when_ideas_have_sex.html
The stone. They were a popular tool during the Stone Ages. Simple to make and use, just sharpen it and then you use it for whatever (say cutting or chopping). One person can understand how to make the whole stone tool.
But we don't use stone to interact with the world. These days we use electronic devices. These are much more complicated than mere stone tools. Not one person knows how to make the whole thing. In the case of iPhone someone knows how to extract oil, someone else knows how to turn that into plastic, someone else knows how to prepare circuit boards and silicon ships, someone knows how to program the chips and the list goes on and on.
Things like iPhone are possible because someone wrote the processes down, these processes are shared and the come together to make great things. As a result, humanity progresses. Just look at how far we've come!
Thats when I realised, we're living in the fuckin' matrix! We use all these tools and equipment to make life easier, but we don't know how they work exactly or how they're made. It's like a fake reality to us - the ability to use and control what we don't entirely understand. Stone tools were easy to understand, but iPhones? mind-blowing. How do iPhones work? But most importantly...