Disgruntled employees may dream of one day walking into their boss's office and telling him that they are quitting immediately. While this may make the employee feel good temporarily, in the long run, it typically does more harm than good. In most cases, the better course of action is to follow the company's rules for a proper parting of the ways and to cooperate with its wishes until the final day.
Quitting without giving the appropriate notice could come back to haunt you. If you don't have another job already lined up, when prospective employers contact the company you left for a reference or to verify your work history, they probably won't receive flattering information about you. Even if you already have another job, future prospective employers may still discover that you left without giving notice. Employers may think something happened to hasten your departure or that you may choose to leave them in the lurch as well.
Breach of Contract
If you are under contract or have entered into a formal working agreement, you may be considered in breach if you attempt to break it without giving proper notice. Depending on the laws of your state and the terms of the agreement, the employer may have the right to withhold any pay still owed to you or limit your right to continue certain employee benefits. The employer may even be able to take legal action against you.
Leaving a job without proper notice not only affects you, your boss and your co-workers, but also clients or customers who depend on you. If you work in a medical facility, your sudden departure could also jeopardize the health of patients because of inadequate care provided by a short-handed staff. Even if your position cannot be filled before your final day, providing notice at least gives your employer the chance to create a plan to fill the void until hiring your replacement.
Situations may occur where giving notice may benefit you and the employer. For instance, if you started a new job and you're two weeks into a six-week training program, you may come to realize that you've made a big mistake and that the job isn't what you expected. Giving the appropriate notice and continuing with the training during the time frame makes little sense for you and does nothing for the company other than waste its money, so you'll likely be encouraged to leave as soon as you make your intentions known.