So, I think the whole Whataburger VS In-N-Out thing is actually not a Whataburger/In-N-Out thing, but that hamburgers are "regional" or "typed" like pizza.
Whataburger is apparently a version of the "Texas-Style Burger" which is heavy on mustard. McDonald's had a "Texas Homestyle Burger" and Burger King has the "Texas Double Whopper" both of which are mustard heavy.
In-N-Out is part of a burger "Family" that I call "Thousand Islands Dressing" burgers. The Big Mac is one of these, and most any "secret sauce" burger is here.
It's a lot like Chicago Pizza versus New York Pizza versus Spokane Style Pizza.
I think there's a "family" of "coleslaw topping" burgers. What other "families" of burger are out there, and why is the Texas-Style Burger the best?
@dolari Mustard, onions, slaw, and chili to be specific.
@dolari Can confirm coleslaw. We call them all-the-way or Carolina-style burgers in North Carolina. Same goes for hot dogs.