Weather the hard times together—the excuse heard most often. You can only clock in and out according to the company’s requirements; the rest of the time does not belong to you. You are under a responsibility-based system before and after work, and must also be on call at all times. When requesting leave, you must find someone to cover your shift; otherwise, you still have to come to work even when sick.
The advantage is that after resigning, you can handle any work-related difficulties with ease.