I ask because I'm generally ignorant on the subject of economics and the assumption that I've operated under for the longest time is that after the Great Depression, New Deal Programs, and the World War II readjustment the United States came upon a stable system of continual growth that went from the 50s to the 70s.
My confusion comes with the idea that a stable economy precludes recessions, with the worst thing to happen being stagnation rather than descent. And it's obvious that wasn't the case, there were more than a few economic downturns before Reagan and I want to understand how under a Keynsian system the economy was still prone to volatile boom-bust cycles.