My family (on both sides) have been 100% Coke for generations...when I order a Coke at an unfamiliar restaurant and the waiter says, "I'm sorry, is Pepsi okay?" I change my order to water. I'm either going to pay for a Coke or get free water....oddly, when I have friends that order Pepsi in a Coke place, the waiter never apologizes and asks if Coke is okay, it's usually along the lines of "We only serve Coke products"
Also, I have yet to find a Pepsi jingle that is just as catchy as the '90s Coca-Cola jingle "Always Coca-Cola"