This is why microeconomics and macroeconomics are different but related disciplines.

By way of analogy, think of the first as physics and the second chemistry (the study of emergent phenomena from the more fundamental relationships). But less rigorous than physics/chemistry, at least so far.

My favourite how different the "home budget" and a national economy works is if you want to save some money for a trip you just stop spending a bit and keep the extra money in a savings account until needed. If an economy did that then the economy will contract, reducing peoples spending power and income.

It's like you're saving for you holidays and your hourly rate goes down because of it.