the fountain concoction

you mean....a "float"?!

I'm with WW on the ickiness of the term "pop." [un-cool-e] In my fambly we tend to say "soft drink" or "fizzy drink."

Two more notes on the subject:

1. If you put a spoonful of sugar in a fizzy drink, it de-fizzes it (something my Mum taught me when I was little!).

2. In the UK, if you ask for "lemonade" when you are in a pub or restaurant, you will be given a carbonated lemon-flavoured drink. "Lemonade" as North Americans understand it is very hard to come by in the UK and Ireland. I think they call it something like "old-style lemonade" (but I am very willing to sit corrected if anyone would like to correct me).

If you can't see the bright side, polish the dull side.