Shamrock Shakes, and their cult following, explained

(via Vox)  Every March, along with college basketball tournaments and the opportunity to misquote Julius Caesar, another seasonal tradition returns: the Shamrock Shake from McDonald’s. Despite not being the fast-food chain’s best-known (or, arguably, best) limited-time product, the green beverage has garnered a cult following over the years — and has a surprisingly interesting backstory.