Oil prices: down, down down again

The latest story on the price of oil says it fell below $113 a barrel today.
I have a little insight into the whole thing because I once did a story in which I called something like a half-dozen oil executives when the price of gasoline went from something like $1 a gallon to $1.25, which seemed atrocious. That said, it's not much insight not is it very insightful.
Every person I talked to stressed supply and demand (leading to my oft repeated joke which I have already posted here, so there's no need to rehash that).
The problem is that its really hard to see why the supply fluctuates so much. One would think that a certain amount of oil would be constantly pumped so the flow would remain steady.
Compounding this, every article I have read during the recent run up offers different opinions about why the price is soaring, how high it will go, when it will snap back and what is causing it. Is it because of an attack on a pipeline in Nigeria? Because of tensions with Iran? Because of a hurricane? Because of too much activity by speculators? Panic over supply concerns in the future? Can we blame China and India? Are all these things working in concert to drive the price up?
The you have the people predicting the price of oil in the next year. They say the price will go down, but the prediction isn't low enough, so the price of oil rises because everyone thinks it won't fall.
Wasn't $50 a barrel some kind of threshold? The only commentator I could really trust (if I could remember who said it) said at the time that once the price of oil breached $50 a barrel, it indicated a fundamental shift in the market and the tendency would be to see how far up it could go. That guy knew what he was talking about.
I also heard a small oil company executive say that when gasoline cost more than $2 a gallon, they saw a sharp drop off in sales. That, I think, was in 2005. Nationwide, the number turned out to be more like $4 a gallon. I haven't checked, but I think the new station he built in 2005 is still in business and going strong.
People used to say that gasoline was a leader item, and that gas stations sometimes took a small loss on sales to get people to come into the store and buy high profit items like candy bars and pop and other convenience store fare. (Has anyone ever bought one of those nas-tay hot dogs on the rotary heaters?)
If this is so, then why did they install pay at the pump credit card readers in such abundance? I never go into convenience stores any more, unless I am on a long trip or I absolutely have to. If gas is a "loss leader," those poor guys must be losing money hand over fist.
I have no idea why oil, and thus gasoline, price go up and down. That's why I get so frustrated. I think other people feel the same way. There's no apparent reason, there's nothing you can do about it, and as a consumer you just feel helpless.