For this country, and this is all going to be a laymen's viewpoint, I saw everything go as a domino effect. First the housing market burst. This caused banks to have to reassess their assets and tighten up the cash supply. Shortly thereafter, they realized, "Holy ****, we have a lot of AAA securities that are garbage and these things are worth absolutely nothing". Those were a giant deduction from the Asset side of the ledger. This brought about all sorts of solvency issues and causes thousands of banks nationwide to head towards bankruptcy. Even the few that were not going bankrupt were not financing to anyone. So if a small business had a giant machine go out, they had to pay cash to fix it instead of borrowing that money. There go more jobs. Plus no new businesses could pop up to fill voids since they could not get loans. There go more jobs. And the list goes on, et al. We all know the story. And none of that even touches on the idea of confidence in the market, which plays a huge role as well.
That is how I look at what happened here in the U.S..