NEW YORK (CNNMoney.com) -- When it comes to treating people poorly in the workplace, the company isn't always the guilty party. Employees can do plenty to mistreat their bosses and colleagues, especially when they quit.

Just ask any manager, small-business owner or beneficiary of an ex-colleague's dumped workload.

But the fallout may not be borne by the company alone. Flipping the bird on your way out the door (literally, figuratively or even unintentionally) can backfire on you and your next employer.

Here are some of the worst ways employees can say sayonara.

Mary Cheddie, senior vice president of people at PRC, recalled a case of a company where several employees quit on the same day after learning their employer couldn't give them more overtime hours. As a final ta-ta, they torched their manager's car.

The company kiss-off came in the form of call to the police, who took it from there.

The urge to tell-off your manager -- and everyone else -- is too tempting for some to resist.

Cheddie knew of a worker who, after giving notice, sent a final email to everyone on the firm's distribution list informing them they'd all rot in hell since they'd failed to join the faithful.

Noting in an exit interview that your tightwad, micromanaging boss can shove her PowerPoint presentations is, well, stupid. The HR person will make a mental note to never rehire Bitter Betty, formerly known as you, and she may just let slip her last impressions of you when someone calls for references.

And unless you're into being threatened with defamation suits, you also might not do what one person Cheddie knew did: call your employer's clients right before you resign and tell them that your company will be shutting down due to financial difficulties and suggesting they go with you to your new firm.

Managers prefer two weeks' notice, not two minutes, unless you don't want a reference from them ... ever. Sure, a company can ask you to leave ASAP when you quit if you're going to a competitor, but you should always give them the option of a two-week window.

When you work for a small business, two weeks is often inadequate since your departure can leave a big hole. Say you're the key sales person. Not only do owners have to find and train someone new, they have to continue wooing the potential clients you lined up, and that's not a job easily transferred to someone else since a lot of sales is based on personal relationships, said small-business owner Mark Jaklovsky of Polar Design.

Giving adequate notice isn't just considerate. It's smart. If you leave abruptly you may forfeit money in the process. The company may only pay you for unused vacation time if you give two weeks' notice. Some companies may even offer severance to employees who voluntarily leave if they give ample notice, said said Emerson Moser, an attorney in labor and employment law at Dinsmore & Shohl.

"I forgot" and "I didn't think that was enforceable" are typical responses exiting employees give bosses when they're reminded they signed a non-compete agreement that almost certainly prohibits their taking that new job they just secured.

The employer may threaten to get an injunction against you to prohibit you from working for the competitor, which also may be sued, Moser said. Some states, like California and Texas, are less likely to enforce non-competes, while others, like Ohio, often do.

Your new employer may send you packing. Or, if you're lucky, Moser said, your old employer may negotiate with you, perhaps letting you leave if you agree never to work with its clients or not to work in a given product area at the new company.

It's tempting to overlook the fact that the work you created and the clientele you brought in to your employer typically belongs to the company, not you. So making off with downloaded files the company considers proprietary can get you in trouble.

HR consultant Ronald Webb of labor relations consulting firm Cruz & Associates knew of a case in which a salesman did just that against the advice of the HR person at his new company. Realizing he made a mistake, he destroyed the disk. But his old employer sued him and the new company anyway.

The old employer didn't win, but the suit took a year of everyone's time, attention and money. "The irony is the salesman left his new company two years after the suit ended," Webb said, making him a very expensive hire indeed.

Before quitting, check your company's policy and procedures manual to assess what your obligations are and what you have coming to you, Moser said.

Then think good karma. "If a company has demonstrated that it's fair to people, try to be fair back," Jaklovsky said.

If possible, do your exit interview a couple of weeks after you leave so you won't be emotional and say something you'll regret, Cheddie said. If that's not possible, and you say something blasphemous, she suggested, you might call back and apologize.

Lastly, keep your eye on the big picture, Cheddie said. "Yesterday's employer could be your current employer's new buyer."

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Worst ways to get fired: No one expects companies to be the warmest, fuzziest creatures. But some of their behaviors can be stunningly (and, you might argue, stupidly) cold.

The get-started guide to making it: If you want to get ahead in the first years of your career, it pays to know when to suck it up, when to step it up and when to move on.

Best companies to work for: See which ones are best in pay, best in benefits and best all-around.

Companies that recently announced layoffs: Intel (Charts), Hanesbrands (Charts), RadioShack (Charts), AOL (Charts)

Companies said to be eyeing them: Ford (Charts)

Jeanne Sahadi writes about personal finance for CNNMoney.com. For comments on this column or suggestions for future ones, please e-mail her at everydaymoney@cnnmoney.com.