The division of labor required to create a simple household tool. 

How often do you sit on a chair? Probably every day. But do you ever wonder how much work goes into making one of them? No one knows how to make a chair by themselves. If you tried, you would fail. First, you would need to chop down a tree. To chop down a tree you would need an ax. To get the ax, you would need to make it yourself. If you know how to make a chair, but not an ax, then you couldn’t make one. And what if you become hungry? You would need food. If you wanted meat, you would need to raise your own animals, butcher them, and cook them yourself. What if you wanted a salad? You would need to grow your own vegetables which takes months. If you could do all these things, you would still need to carve the tree into a chair and if you don’t know how to do that, then you need to make a machine that does do it. You can’t do this, so you can’t make your own chair. Your not dumb, it is just not possible.