The Revolutionary War, and the events leading up to it, are the kind of things that stick in your mind. There's dudes dressed as Indians throwing tea into the ocean and "no taxation without representation!" and Washington crossing the Delaware and a ragtag band of ewoks defeating the Empire.
And then there's the utterly forgettable period during which we had the Articles of Confederation. Until I went on wikipedia and looked it up, all I knew about this period was that in some vague way things weren't centralized enough and didn't work. (Which is embarrasing, because actual historians sometimes read this blog.) And as far as I can see, things were pretty awful. Without the power to tax, we couldn't raise an army or give veterans their pensions. Since we didn't have a proper navy, Barbary pirates would enslave our sailors. The money of an insolvent federal government became worthless. Since we hadn't assembled into any sort of functional economic bloc, Europeans would abuse us in trade wars.
Of course, this is mostly the boring kind of awful. You can easily make movies about American patriots triumphing over the British in the Revolutionary war, but the move away from the Articles and towards the central government that made America a functional and eventually awesome nation isn't summer blockbuster material.
This is an unfortunate thing. More attention to this time period would make the valuable point that having a strong central government is a very helpful thing in the modern world. Without taking lots of power away from states and establishing a working federal government, we'd be in chaos with a failed currency, no army, a terrible economy, and enslaved sailors. The way we got out of those problems deserves to be a bigger part of our national myth than it is.