There's just so much risk involved in staying. To riff on two3zone's example, it's like being offered your dream job out of college (maybe working at Google or Goldman) right when you are about to go off and backpack Europe with your best friends. You can say no, backpack, and hope that you're just as desirable after a year, but it's a risk. Maybe next year you get an even better position in the same company because the economy is doing great and there's huge need. Or maybe they don't look at you the same way because you're older or the professor who recommended you isn't as influential anymore. You may not be successful if you take the job, but you may not even get the opportunity if you don't. There's no universal right answer, just choices and risk.
There is risk involved with leaving before your ready also.