When in highschool, my daughter worked as a busser in a Village Inn a couple of blocks from the house. She used to giggle at the customers who came in and ordered a Diet Coke Float.
I get that, but sometimes there's logic behind it.
I don't like regular coke, or regular any kind of soda. Too sweet and makes me thirsty.
However, it's not just the taste. If I decided to splurge on something, I figure that's no reason to completely go to hell. If I wanted a float, I want it for the ice cream (which, as everyone here knows, makes me fart, so I really don't want it) taste mixed in, not to take the attitude to purposely make it as "bad" as possible.