OK, yes, it's theoretically possible for a society to try to save too much (especially if the ways they try to save it do not allow their savings to get put to good use -- to get passed along as credit to those making valuable investments), but you'd have to be delusional to think we live in that society! My semi-apoplectic response is at 43:20.
Points I didn't get a chance to hit: It's possible for the economy to grow through producing better, more valuable stuff, rather than just more stuff. And it's possible for the economy to grow through efficiency and productivity (using the same amount of raw materials and labor to produce more or better stuff).
People who make profoundly stupid economic arguments that parrot Bush/corporatist propaganda (in the face of terrorism and war, it's critical that Americans not stop shopping!) irritate me. If this means I'm expressing "self-righteous indignation," fine. :-P