You've got OPEC a collection of countries that don't all like each other, trying to agree to lower their individual production knowing that they can't trust each other.
At the same time this exact group of countries are running deficits and any cut's they make will increase those deficits in the short term. Keep in mind these are countries who can't be described as stable. In many the only thing keeping the government in power is they oil money they sprinkle on their populations.
You've got oil producing countries outside of OPEC who would love to see the price of oil rise so they can expand their production of oil that's more expensive to produce. Keep in mind there is a prominent theory that OPEC flooded the market with cheap oil to drive these countries out of the oil producing business.
You've got world economies that depend on oil, all of which are using cheap oil to prop themselves up to differing degrees. A return to $100/barrel oil would be short term trouble for many 1st world economies.
I love the oil market. I can't figure it out, but I love trying:)