Five Guys has a quaint novelty by offering free peanuts while you wait and you can simply throw the shells on the floor. Don't laugh. There used to be a famous franchise in Carolinas that locals and tourists flocked to. Very simple setup, easily repeatable/managed. They have a sign to tell you were the potatoes came from for the particular season.
Smashburger from the Colorados which has these thin gourmet fries with olive oil and italian spices. A common gourmet touch in a lot of big city foo-foo restuarants.
My favorite: Culver's with their butterburgers and fresh frozen custard made daily ( That's ice cream for you heathens.) I was seriously waiting for this IPO for 3+ years to back the truck up. Their theme is being a wholesome, family oriented joint. And if you go to Wisconsin, you'll see 3 Generations together! The place is staffed with people straight out of Archie comics. When I brought my Mom who has only lived in America for 20 years there, she squeeled "how cute!" at our girl at the register. I almost died.
And countless other burger joints...