People talk about Obama as if he had been elected king and all he had to do was decree that his policies would be turned into the law of the land. Every single thing that he has tried to do has been beaten to within an inch of its life by the Republicans in Congress. (Which, of course is their prerogative. The country voted them in.)
Forgive me if this is too "inside politics", but regardless of one's party affiliation, I see the following things happening:
Fact A: The US is divided about how to govern the country. The voters may shift from one party to the other, but only marginally. There is a very real difference of opinion.
Fact B: The parties themselves have members that are all over the map. There are both liberal and conservative Democrats. There are moderate Republicans and Tea Party supporters.
Fact C: No party can act unilaterally. Neither party can push their agenda through without losing members of their own party and picking up some votes from the other.
Fact D: Each party can, however, block the other's agenda. Saying "No" is easy. Finding something that the right number of people will say "yes" to is extremely hard.
Fact E: Compromise, once the tool of statesmen, has become a dirty word. If the only way to get a piece of legislation through is to make it more appealing to the opposing side, Congressional leaders will usually prefer to let it go down in flames and blame the other side for it's demise. This is bad when we are talking about health care or tax policy. But it's absolutely disastrous when doing nothing means that the government shuts down or the country can't pay its bills.
The miracle, to me, is that anything manages to get done at all. The fact that Obama has gotten health care passed (many previous presidents have tried, none suceeded), repeal of DADT, stabilized a financial meltdown, kept to a steady schedule of withdrawl in Iraq and Afghanistan, and kept the government open and running is pretty freakin' amazing.
Just my opinion.