The big burger chains are exploring and/or making trial runs with automating a lot of their jobs. The cooking will be done by robots and cashiers will be replaced by machines where you punch in your order and pay for it without human intervention. Essentially they just turn the cash registers around. The only humans left will be one person to hand you you order, and another to mop the floor.
These used to be the jobs where high school students started out, learning basics skills like showing up for work on time and not pissing off the customers (or the boss). I don't know what all these kids will do in the future.
This is one reason why I don't like raising the minimum wage. Part of your pay is learning those basic skills. Nobody wants to pay somebody who doesn't know what they're doing $20/hr to do it. After you've proven yourself, you move on to a better job.