I'll go with a Catch to a wonderful post by Dylan Matthews that goes through all the reasons why government budget deficits are thought to be bad -- and why each of them is either wrong all the time, or wrong some of the time.
It's very, very, good. It doesn't draw any hard-and-fast policy conclusions about what to do right now, but what it does do is explain that some of the anti-deficit rhetoric is pure fantasy that we should ignore, while other arguments are more serious.
I'm not sure that it really does answer the question, however, of why people love balanced budgets so much. I have a piece coming out sooner or later on that...I really don't think we do know the answer. But Matthews definitely captures the rhetorical support for eliminating deficits and why much of it -- but definitely not all -- is pure nonsense.