Casual, be yourself, and be know what you're looking for in a job. They didn't like being unprepared. Ask plenty of questions, and clearly state if you're looking for overtime or not because they'll work you hard.
I applied in-person. The process took 1 day. I interviewed at The Hound (Auburn, AL) in Mar 2015
Interview
walked in the door, shook the manager's hand, asked some basic previous experience questions and hired me on the spot. I had previously worked for the company so it made sense for them to hire me back as I familiar with the policies and protocol.
I applied in-person. The process took 2 weeks. I interviewed at The Hound (Auburn, AL) in Oct 2013
Interview
They call you in to sit down and chat, get a feel for your qualities, experience, why you applied, who referred you, etc. They might ask a few situational questions depending on the position you're applying for, but not necessarily. The manager is different now from when I was hired but he's a chill guy. You might go in a second time for a follow-up interview/hire, if the first time was a short screening interview. They're looking for nice, down-to-earth people that don't get worked up about anything and are easy to get along with, but they don't hire slackers.