Topping off your gas tank: Habit of harm?

It may be a habit of yours to top off your gas tank in order to round the price to the nearest dollar. Although this practice seems benign, it actually harms your car, the gas pump, and the environment. Topping off your gas tank can result in your car's vapor collection system being ruined, causing your car to idle sporadically and possibly stop working. The excess gas can evaporate into the car's vapor collection system which, in addition to the aforementioned problems, can lead to higher gas emissions. Adding extra gas to your tank can damage the gas pump by causing the pump's vapor recovery system to fail; this failure could potentially cause the pump to stop working entirely. One surprising fact is that much of the excess gas that you think is going into your fuel tank is actually being absorbed into the pump's storage system. In other words, you are paying for gas that you don't get and filling the pump's hose for the next person in line (a nice, silent boon).  In terms of environmental harm, topping off your gas tank can increase your car's emissions as well as cause gas to spill, wasting gas (and your money) and polluting the air.