Pardon the know-it-all coffee shop nerd humor here, but I love it when people come into the coffee shop and order a large latte rather than their usual medium because "they need that extra push."
Both medium and large drinkies come with 2 shots of espresso (and so it says on the menu). That jolt they're looking for must be in the extra 4 ounces of milk that comes in the large cups.