Why did Bush leave the economy in such big mess when he left office?

At the time Bush left white house, the economy was losing 600,000 jobs a month (january 2009), multiple corporations were brought to their knees and bankruptcy (aig, chrylser, gm, fannie mae, freddie mac) etc etc. unemployment 10%. consumer confidence all time low and people defaulting on mortgages right and left. Just at that point, Bush said goodbye to the American people and went into retirement. Now when he started office, economy was on the top. Huge surplus, very low unemployment and many companies doing well. Finding job was so easy when he start office. And now the conservatives are mad on Obama? How come they were quiet on Bush?