Economic stimulus or austerity

The US implemented economic stimulus to deal with the economic crisis. UK and Germany decided to implement austerity measures to cut down their deficits. These countries have top economic advisers. Why does one country decided to adopt stimulus while two others decided to take the opposite measures?

Economics is an imperfect science. Expert economists have two views. They said, "one the one hand, we have to do this. On the other hand, we have to do that". Some government leaders are so tired of this type of talk that they are now looking for economic experts with one hand (just a joke!).

What is the correct action? Nobody knows. Each person, economic expert or non-expert, can have his view. I prefer the US approach. I do not see how the economy can get better if more people are unemployed due to austerity measures.