to ALL...

I've heard that topping off, or filling to the brim, can damage the charcoal filter cannister in the emissions system.

"The EPA also warns consumers that topping off can affect the performance of your vehicle. This is because your car or truck was designed to have additional room in the gas tank. The vehicles are configured in this way to allow room for the gas to expand. When you top off, you are eliminating that room for gas expansion; instead, it will evaporate into other areas of the vehicle, like the vapor collection system. This will cause the system to work improperly, leading to poor performance and higher gas emissions."