It's a tourist thing. People hear In-N-Out is "good" and, frankly, the burgers are pretty damn good for the price point. But it's about going to In-N-Out, getting a t-shirt, and taking a selfie with your bestie surrounded by 50s diner decor, and then, continuing on your road trip or whatever.

There's always a place nearby to get a "better" burger, and you could pull better fries out of a store-branded bag of frozen "seasoned potato sticks", but the food ain't the reason people go.