I'm willing to bet...

I'm willing to bet that you don't care (as judged by your actions) as much about the price of gas as you think you do. Case in point: right now, it's a safe ballpark assumption to say that gas prices have been going up 2 cents per day, every day. Do you (a) fill up every day, so that you get as much gas for as little as possible before the next price increase, or (b) just wait to fill up like normal when you are running low.

Let's asume that you burn a gallon of gas each day, and that you fill up once every 14 days (for 14 gallons). Assume that the price of gas started at $3.00 a gallon, and the price goes up 2 cents each day. If you fill up every day, you spend $43.82 on gas. If you fill up like normal, you spend $45.64. "Big deal," I hear you saying even now, "it's just $1.82." And you're right. But that $1.82 is the same as getting gas 13 cents/gallon cheaper. At a local Save-Mart, I can save 5 cents per gallon if I spend $25 in groceries, 10 cents if I spend $50, and 25 cents if I spend $100 (up to 15 gallons). I went for the 25 cent discount once, and did my regular grocery shopping there. I put in 12 gallons, and so saved $3. It's entirely possible I more than made up the difference in higher prices, but I don't follow those too closely.