So you think In-n-Out has a monopoly on secret menu items? Think again. Whataburger, too, has a secret menu that goes well beyond just your average burger and fries. In fact, some of the best items at Whataburger aren't even listed. There are drinks, brunch, and Southern classics to be had on the Whataburger secret menu, and if you don't know about them, you're missing out on the real reason people love this Texas burger chain so much.