I know it should be a warning sign to just not drink coke, but I've instead taken it as a "this is literally for filling a glass already prefilled to the brim with ice like in the ads" kind of thing.
Because undiluted coca cola is just honestly not very good, and extremely uh, I'm not sure how to put it, practically pungent
Like coffee: I like a hint of sweet in my espresso, but Cola is like dumping 4-5 spoons in a small cup of coffee. Becomes sugar syrup and that's all one can taste anymore.