I used to work for this one particular McDonald's restaurant part-time as a second job. I quit when I did the math on one of my paychecks and found they were shorting my pay. I wasn't the only one. One of my shift leads confided in me that when they promoted him they intentionally kept paying him crew member pay rather than give him the raise he was owed with the position. They also told him he wasn't needed at a meeting then wrote him up for not attending that meeting.
I didn't contest my own pay issue because the owners were shit people. The wife (a married couple owns all the McDonald's in my area) would randomly come in and start verbally abusing the employees about how they weren't doing their job the way they expected. There was one incident where she was verbally abusing my coworker in drive thru about how he wasn't doing his job efficiently but at the same time she's doing this I can hear over the headset the customer waiting for him to take their order. When I went to speak up she tried to shut me down, saying she was dealing with him. I still spoke over her and informed her there were customers waiting. She felt they could wait while she finished verbally abusing an employee so I got on the headset (I was taking cash) and took their order while looking at her. This wasn't the only incident. I've witnessed her get into arguments with customers over something as stupid as the customer wanting extra salt.
So when I did decide to quit I walked in one morning as if I was showing up for my scheduled shift and placed my uniform on the counter. I told them I wouldn't be working that day or any other days thereafter.
Now, my fiancee is working for the same location. I told him ahead of time how they have a tendency to screw their employees over. However, his experience has been worse. After hiring him they didn't have him scheduled for two weeks. Yet they would call him in and ask him to work every day. If they asked him the day before they would put him on the schedule for just that day without telling him and then call demanding why he wasn't at work when he was scheduled that day. They then would schedule him on his days off, not tell him he was scheduled, and call him to tell him he was over an hour late. The little handle on the drive thru window (something they didn't replace during the remodel) broke off when he was opening it and the manager told him it would come out of his pay. When I asked if maybe she was joking he said no she was angry and serious. He said it looked like it was hot glued on to begin with.
Since he started working there they would call him in on his days off (as stated) ask him to work later than his scheduled time, sometimes as late as 12 hour shifts. In our state any day over 8 hours is considered overtime. So, he came home sick last night and was sick all night. He called in 2 hours before his scheduled shift to tell them he was too sick to work. Of course he had to call repeatedly to get an answer. Their response was to tell him they were going to write him up for his first ever fucking call off because it was less than 3 hours before he was to start work. The same people that would call him up on his days off and expect him go show up to work immediately on demand are writing him up for giving them a 2 hour notice that he was sick even though they weren't answering the fucking phones.
TL;DR: McDonald's is shit, the owners are shit. They short your pay and write you up just for calling out sick or not showing up to a meeting you were told you didn't have to attend.
Edit for typos