Small company I used to work for hired a guy who had been laid off from a previous job - let's call him Jeff. He had some business management experience, but the company's philosophy was "everyone starts at the bottom" (that alone is a terrible business practice, but not what I'm referring to). Eight months after Jeff is hired, the office manager walks out due to a disagreement with the owner. Owner tasks Jeff with doing the old manager's job and tells him "if you do well enough, we'll give you the job permanently." Jeff absolutely killed it; he handled problematic customers with patience, delegated tasks to people he knew could handle them bets, and implemented a few systems that made the business run more smoothly. The holidays roll around and the owners hire a new person from out of state - we'll call her Janice. Janice has a similar story to Jeff's; thought she had a steady job, got let go unexpectedly, needed anything that could pay the bills. Rather than start Janice from the bottom like they did with every other employee, they had her shadow Jeff in the event Jeff went on vacation or was hit by a truck. Makes sense, I guess. Again, Jeff rolled with it; Janice was pretty slow to learn anything and outright stated there were some parts of his job she would not do under any circumstances, but she'd do in a pinch.
I mentioned that they hired Janice around the holidays because the company always shut down the week between Christmas and New Year. The last working day before the shut down, the company had a small party, and while one of the two owners went with Janice to pick up the pizza, the other owner said "Jeff, you've done an awesome job this year and have been an asset to our company. Take the rest of the day off (after the party, of course), and when you come back in January we'll have a talk about your future here." Everyone was thinking "alright, cool! Jeff's gonna get promoted." Yeah, no. It took a few months for the truth to come out, but here's what happened: The owners decided that while Jeff was a fantastic manager, he didn't have the "face" they wanted for their business - they much preferred a slender blonde woman to be the first person their customers saw instead of the tall burly guy who looked like he just crawled out of the woods behind the place. So despite the fact that Jeff had practically carried the company for eight months, they gave Janice the promotion instead. When Jeff protested and said they had promised him the job, they claimed they never promised him anything and he "should be glad to even have a job in this economy." If that wasn't bad enough, here's where it gets worse: the "talk" the owners had with Jeff was "as a thanks for keeping us going, we're giving you a small raise and changing you from hourly to salary - so while you won't make overtime pay anymore, your paycheck should still match what you were making previously."
Naturally, the owners didn't tell everyone they'd screwed over their best employee - they just told anyone who asked that he turned down their offer and forced them to give it to Janice instead. When Jeff learned they were lying about what happened, he decided to (metaphorically) burn the place down. When he was training Janice, he would save her before she made a big mistake and even though quality control wasn't ever his job, he was really good about catching errors before they went out the door. If Janice couldn't figure something out, he'd tell her he was busy (which was usually true) and for her to get someone else. If she or the owners demanded he drop what he was doing to assist her, he'd do the minimum necessary and often make an offhand comment to the owners about her incapability to do the job unassisted.
After almost two months, Jeff got called into the office where the managers threatened to fire him if he didn't shape up - he asked them to point to what aspect of his job they were unhappy with, and everything they replied was met with "that was my task when I was the acting manager, now that you have a manager, that is no longer my responsibility." They tried to counter that he was the *assistant* manager, but he responded that his official title in their system was still "expert" (i.e. regular employee) and that he hadn't agreed to accept a position as an assistant. They tried to say "fine, you're an assistant manager now", but he declined the position; they replied "you can't refuse this, we're making you the assistant manager". Jeff shot back with "Oh? Well according to the lie you told everyone in the shop, I 'declined' the position you gave Janice. Now you want to tell me I can't refuse a promotion when it suits you? If you do this, I will do two things: I will quit right now, on the spot, and on my way out the door I will tell everyone in the shop every detail about how you stabbed me in the back." The fact you're reading this now should tell you what choice the owners made.
What's funny about this is that Jeff was actually disappointed to quit the way he did - he had a new job lined up and was starting the very next Monday, but he was hoping to drive the owners to the point they tried to pull the "you should feel lucky to have a job" line again. Anyway, Jeff enjoyed a week of unscheduled time off and went on to greater things, and the company realized just how much they relied on him. Janice quit about three weeks later because she "couldn't handle the stress", and the owners actually fired me for putting in my 2 weeks notice when I got a job offer somewhere else. Somehow the owners kept the place going for about two more years before folding, although I hear they moved elsewhere in the state and tried again.