Having been born and raised on the West Coast, the drink was always called pop to me. It was only when I moved to New Jersey that I had to get used to calling it soda (or in NJ - "soder"). When my dear mother came east in the middle of August to visit me, she learned the lesson quickly. Stepping into a McDonald's in the Village, she checked the reader board and saw on the lists of sodas, that they had Root Beer. When they handed her the cup, she looked at it and said, "Where's the ice cream?" I don't know who was more confused, my mom or the McDonald's employee.
<A Root Beer Soda!>