The Shirley Temple Effect occurs when one person at the table orders a Shirley Temple and everyone else orders one/changes their drink order to a Shirley Temple as well.
Person 1: “I’ll have a Coke”
Waiter to Person 2: “and for you?”
Person 2: I’ll have a Shirley Temple
Person 3: ooo I’ll also have a Shirley Temple
Person 1: Can I actually change my Coke to a Shirley Temple?
Waiter: Ah yes, the Shirley Temple Effect