In johndageek's reply, he mentioned that he had already accepted the new offer before tendering his resignation. Since that acceptance usually involves signing something, I would agree - quitting a job you haven't even started is crazy.

That said, does anyone have the converse experience where they have an offer, have not yet accepted it, tender their resignation and get a counter offer? I'd love to hear those experiences, how they worked out (whether taking the counter or not). Personally, I think my boss realises that I'm looking out for my own best interest^1,2, thus would never trust me less just because I got another offer, and my current employer had to counter offer to keep me. But I may be deluding myself - stories to help convince me either way would be appreciated :-)

¹ I moved about 2.5 years ago. I don't mean a move across town. I mean a move two timezones away. It took us over 30 hours of driving to get to our new home. When I told my boss this was what I wanted to do, we worked out an arrangement to make both of us happy. He did raise one concern: that once I got here, I'd be looking for other employment. I told him that as long as I was getting a better deal with them, there was no point to looking elsewhere (I do work for a relatively large company). Of course, being 2.5 years later now, if he didn't trust completely at that time, he probably does now.

² I make no qualms that the only reason why I want to make high-quality software is not to make customers happy or ecstatic or any silly buzz term, but to keep the customers from calling for support. This, in turn, will reduce the amount of my time that support takes from me in solving customer problems. The more time I spend on support, the less time I have to work on the next version of our off-the-shelf software. The less time I have to spend on the next version, the less productive I am. The less productive I am, the worse my yearly review. And my yearly review translates directly (at least in this company) to yearly bonus and the yearly salary review. This is not about the customer. This is about my take-home pay. As of yet, my management structure has had no problems with this. In fact, I'm betting they wish others would take the same cause-and-effect view of their own contribution to the product. :-)