Not all fast-food chains are going to operate smoothly across the board. It could be a matter of a terrible manager, or so much overturn that the folks working the machines and cashiers never have enough time to catch up. Based on this throwback story from Redditor u/atypical_lemur, it sounds like they had one of the more unfortunate experiences working at a Wendy's.
They wrote, "When I was in college I quit a Wendy's the first night. This was in the mid '90s. I got hired and they asked could I start that night. I didn't have anything going on so ya, sure I'll be there 6-10. After not more than 30 minutes of training on the registers and drive through procedures I was told that I would have to watch the DT and Front End by myself for the rest of the night. After 7 there was literally 3 people in the store, me running the front end, a cook running the whole kitchen and a manager sitting in the office.
At 10 when we closed I was told I wasn't allowed to leave until xyz are done, which I get as it was a closing shift, but that wasn't explained to me when I was hired or asked to work, I was asked to work 6-10 and I had class the next day. So, since I'm not a complete [slacker] (also young and didn't want to burn bridges, or was stupid or didn't know any better), I stayed until past midnight doing the closing stuffs. When we clocked out I told the manager I would not be back again. I'm not even sure if I ever went back to get a paycheck and I don't recall ever even filling out paperwork to be hired."