There was a lot of slipping and sliding going on in my 5th month here. I got this response from the original blog. Why do people "slip"
"There's an easy answer. They DIDN't work hard. They TALKED hard. If you've been here long enough you can spot them a mile away. Said what they thought sounded right, what we wanted to hear, all the things that made it sound like they were in it to win it. But it always sounds off somehow. And they are the ones who come back and have 'slipped'. And yes, even after years of quit - they will slip because they didn't mean it. The option stayed open.
By the same token you can tell the ones who mean it. We almost never see them back here having slipped.