Always outside with a smile and a cold bottle of water.
A good tip to remember is that when you are returning your car if you are like me you usually just put the name of the airport into your GPS and let it take you there. Then you follow the signs for the rental car agency.
In the case of Phoenix their rental car agency is a nice distance away from the airport. So it's best to put the actual rental car facility into your GPS and let it direct you straight to the return facility. If you put in just Skyharbor airport you will be forced to drive through the entire airport complex and come out on the other side before you are able to then drive towards the rental car facility. It is a long detour.