I found #2 interesting:
Stations earn on average between 10 and 15 cents on a gallon of gas. Ironically, they earn the least when prices are highest. When fuel climbs, gas stations must shrink their profit margin to remain competitive, meaning they earn less per gallon than usual. But another big cost during tough times is something they can’t do anything about—credit card fees, which add up to about 2.5 percent of all purchases. When gas is at, say, $2 a gallon, the station pays credit card companies 5 cents a gallon; when gas hits $3, that fee becomes 7.5 cents—more than half the station’s entire average profit.