Customers: My particular location is nearest a high end retirement community, so the majority of my customers are snobby, rich old people. But customers are always going to drive you insane in retail. It just comes with the job.
Coworkers: You will get 99% of requests as long as you are reasonable. They will definitely work with your school schedule. They had scheduled me into my class time before, and they always changed it once I told them. But my boss is fantastic and I love him. Your boss may be different. One of my coworkers changed stores because her boss would scream at her in front of customers. Mine has never even raised his voice.
As for pay, the $15 per hour mentioned is only available for full time employees, though part time also pays very well. For obvious reasons, they are not quick to hand out full time work unless you already have a lot of experience with them. I started part time on register and worked for almost a year before they took me on full time. But I love it and have been a part of Hobby Lobby for 2 years 5 months. I am the head of the Art department and Toys & Hobbies department, which mostly means controlling the stock. I am also a certified framer and I assist in the management there as well. Hope this answered your questions.
Summary: Any job really depends on 3 things. Your coworkers, your customers, and most important, like Katie said, is your attitude. And the first two will vary by location. I've worked for Hobby Lobby for 2.5 years and I love it. The pay is all around good.