This must be a regional thing. I've never heard of a milkshake at the Whataburger in my area... And gravy with fries and a burger? Maybe I need to visit them again. I never been out west, so I can't comment on In n out.Whataburger stomps In-N-Out.....
I had Whataburger when I was stationed in Camp Pendleton in 2000 and had In-N-Out in Dallas 2 years ago...
in the span of that decade, the food tasted "ok", but far from the amazingness that is served up at Whataburger.....
if you can't even offer to serve up country gravy with your fries or burger or anything else on the menu, you don't even deserve to be mentioned in the top 5 fast food burger chains....
.................and In-N-Out can't even whip up a decent shake......