A fun controversy:
What generic term do you use to describe a drink such as Coca-Cola, Sprite, Pepsi, 7-Up, etc.?
You can submit your choice at this site. There is a map of the results submitted. And, at Strange Maps you can see a national map by county based on use of the terms Soda, Pop, or Coke.
Where I live, the majority of people say 'Coke'. I find this humorous; at my office, by majority opinion, Pepsi brand products are stocked in the drink fridge. Beer, of course, would have been the first choice, but that was vetoed for obvious reasons.
What do I say? My dad was from Chicago; my mom from Philly. I think it was a compromise: Soda-Pop. Not Soda. Not Pop. But Soda-Pop.
Another common word usage in my neck of the woods that makes people from elsewhere laugh: there isn't such a thing as a 'potluck' dinner; it's a pitch-in!
I can't explain it for the same reasons I can't explain why the locals pronounce the word wash as if it is wahrsh.