American: "Why do you put that chocolate stuff on your bread rather than Jiff peanut butter?"
European/Wannabe European: "1. It's called Nutella. 2. Because I'm a Eurolitist. And 3. You're an idiot."
Referenced on a little known parenting website. Symptoms include regularly being rightly pissed off.
Not to be compared to Clairecitis which instantly renders its victims utterly humourless while lasting effects includes sanctimony, disdain and boredom.