We -- us humans -- tend to measure everything in an instant. We expect most things to happen the way they go down on television, a medium that helped create and masterfully captures short attention spans. Now, we tap a touchscreen and get what we want instantly. That's great, but it clouds our view of how things sometimes shake out in the world.
Generational trends and once-in-a-lifetime transformations do not begin and end overnight. What we're seeing in spaces such as e-commerce and social media qualify as pretty damn big.
If you see irrationality in a stock such as AMZN (or, to a lesser extent, FB), try to trade the urge for instant gratification for something closer to the sensibility of a geologist who thinks in large chunks of time, such as centuries, not years or even decades.