The food at those restaurants is actually made fresh. They dont have 3 double cheeseburgers just sitting there waiting to be put in a bag. They have to make them. The reason its called "fast food" is because they have tools that make the food cook faster. If you're just ordering a value meal or something, its usually ready within 3 minutes. However, if you're ordering a lot of stuff, it takes time to make it. And if they run out of, say, chicken, they have to wait until it comes out of the fryer before they can make your sandwich (which usually takes about 5 minutes depending on what kind of chicken it is). So instead of making everybody in line wait longer, they pull the car up and give the next car their coffee or whatever they ordered. If you just ordered a soda, would you like to wait 5 minutes for it so some guy could get his chicken at the window? There is a method to their madness.