The question Coke's ads answer is not just Pepsi Or Coke, it is To Coke Or Not To Coke. You always have the option of drinking water. Water dominates Coke as a beverage for health, it (perhaps) loses on taste and texture. Hence a lot of advertising stressing Coke's positives. How do you know that when you say it tastes fairly good that they haven't gotten to you too?

That's why we skip ads in my house, they are just too hot to handle.