I know what you are thinking...... this is another case of a student not liking a class that might be hard... no, it's not that. I assure you. Besides, Corporate Finance is the bane of my existence, not Macro.
Keynsian economics are part of macroeconomics. Based on John Manyard Keynes' theories, this is, put simply, a model of how the government tries to push the masses into to spending themselves into debt so that the United States can boast a higher GDP. Don't worry, the government pitches in themselves and they are the frontrunner in the debt-racking up race.
Personally, I find it to be a childish shirking of responsibilities for some shallow outdoing of one's peers. Is it really going to kill us if we don't have the highest GDP one year? Isn't more important to pay down the debt? In the process, we pay more and more interest in that debt that the government racks up.
In general, I think the goverment dollars are spents on whims of the politicians. They sign off to give government dollars to this and that special interest group, you know, whatever group belongs to the guy with whom, they play golf and frequent the titty bars. Maybe, the lobbyist just adds some dead presidents to their pockets, instead. Either way, it's all about the politicians whims churning their way into the aggregate this and the aggregate that. Everyone's corrupt and being in the land of the free only means we're better off than living elsewhere but, there is no country where one can escape the politics.
Finally, if you don't believe me, listen this guy. He points out that no one follows keynsian economics but the government. Well, the government is the most poorly managed entity out there and everyone knows it.