Many corporations and the people that run them make it hard for the workers in the lower tier to enjoy their jobs. Sometimes too much stress is placed on workers with simple jobs. I once worked in a store with a discount card that cost money to purchase. You would have to go through an entire spiel about the card just to sell one three dollar item. Cashiers hours depended on their ability to sell this card. Some eventually lost their jobs because of low card sales, no matter how well they performed otherwise.
I worked in a second hand store once. I thought it would be fun and I would be able to help people. It was a real eye opener working there, it was the worst job I have ever had. Managers would scream at you to work faster. They expected you to get an impossible amount of product shelved. You could never do well, it was a losing battle. They even followed you to the bathroom! I hardly believed a coworker when she told me that until it happened to me. I was working and had to go to the restroom. When I came out of the stall the manager was standing there, it was bizarre. To make matters worse occasionally people would donate a big bag of clothing and before they brought it in they would squat over the bag and take a big old dump in the middle before tying the bag. A few times women would donate underwear with bloody pads still attached. When this happened we would throw away the whole bag, but we had to open it to see it first.
I once worked in a factory and watched a coworker work a double shift. In the last ten minutes of her day she caught her arm in the machine. She ran to the first aid stand and when she saw the blood she fainted. The cleanup crew were stepping around her to clean the machine and managers were yelling for the workers not to stop production.
Sometimes when you are following all the rules and doing things properly they look for some way to change things on you. You can never be secure, you can never be completely confident. I've been on the job where customer service is number one priority. I actually witnessed a completely drunk woman complain about an employee being rude to her. The woman could not keep her eyes open, stand up straight, or speak without slurring her words. After the manager spoke with her the employee was actually reprimanded and sent home.
I need to wrap up my meanderings here. I guess my point is there is a great deal of stress at the bottom, where you wouldn't expect it.