The next day, your boss calls you in to tell you that the company wants to give you a raise, or a promotion, or maybe the assistant you've been asking for but not getting for the past year.
It happens all the time, and the harder your company tries to lure you back, the tougher it sometimes is to decide between going and staying. Let me try to make the decision easier for you. Go.
There are exceptions to this advice, to be sure. The offer you get from your current company may, in fact, be so good that you'd be foolish to ignore it, never mind that you've made a commitment somewhere else and never mind that you haven't been happy with your present company for a long time. But the counter offer had better put you into a position of power. If it doesn't, the chances are you're going to be looking for a new job within a year after you accept the counter offer.
I have no hard data to back up this view, only personal experience. In most of the situations I've observed, a person who gives notice and then accepts a counter offer to come back with his or her original firm is generally no longer with that firm after a year (particularly if the counter offer simply sweetens the pie in the existing job). And why should it be otherwise? If you were looking for a new job in the first place, you were probably dissatisfied with more than one aspect of the job, and it's unlikely that the counter offer will get to the root of that dissatisfaction.
In some cases, in fact, the counter offer could worsen these problems. Let's say that a prime source of dissatisfaction is friction between you and your boss. Uneasy with the prospect of losing you, your boss offers a substantial raise. But will the raise ease the friction? Probably not. It will more likely increase the friction, because you will now have your boss's resentment to put up with, too.
Trust your earlier instincts. You made a decision to leave your present job because you weren't happy there. You made a decision to accept the job you've been offered because it seems to promise what you've been looking for. Don't disregard the counter offer entirely. Be gracious. Tell your employer how flattered you are. Stay on good terms. But don't let the counter offer blind you to the reality of the situation. If you're swimming across a lake and you're more than halfway across, you don't try to swim back when you start getting tired.
What If You Made a Mistake?
Now let's change the script. You get an offer, accept it, give notice, and start on your new job. Within two months, it hits you: you made a dumb move. The company you joined is nothing like you expected. Your job has turned out to be boring and demeaning. Even the added money isn't worth it. You'd do anything to be back in your last job. If you had it to do all over again, you'd never have left.
The best thing to do in this situation is to go back to your original company and see if you can get your old job back again. You heard me. It's not a defeat (not under the present circumstances). It's the most intelligent way to get out of a bad situation. Chances are, if you were good at your job and you left on pleasant terms with everybody, your company will be happy to accept you back. (Then again, your employer may be one of those companies that never forgive an employee for leaving, in which case your chances of coming back are slim.)
It's possible they haven't found your replacement yet. Or maybe your replacement isn't working out. The point is, in this particular situation, your former company is your best shot, so take it. Call up your old boss. Suggest that the two of you get together for lunch or for drinks. You never know: the boss may bring up the matter and tell you how much everybody wishes you were back.
Of course, if you do go back, try to arrange things so that you're not going to be itching to move again in a few months. The two- or three-month separation should be just enough to allow you and your old boss to develop some ideas on how you might get more from the job and give more to the company. Don't worry so much about money (unless money was a big problem in your last job). Concentrate on the day-to-day aspects of the job itself. You may be putting on an old pair of shoes, but it's still important to get off on the right foot.
