Very casual and relaxed. In my experience interviews were mostly just sitting down and chatting with the manager about what you will be doing if you take the job. They aren't very picky and will likely hire you if you are nice and at least semi-professional.

It was a brief interview with the branch manager in his office. He primarily wanted to know if you were going to show up to work on time, wouldn't let your personal fun interfere with your job performance, would you dedicate your time,(read personal time too) to the company.