So, I came aboard. The principals had just left for an extended sabbatical (they departed shortly after I interviewed with them). Morale seemed excellent when I started, and there was a great deal of interesting work to be done. When they returned, the mood changed very quickly, and it didn't take long to understand why.
I spent enough time there to do some interesting things, and help them over a knowledge slump during an infrastructure forklift, but it quickly became apparent that the owners and I had different ideas about how people should be treated, and how businesses should conduct themselves. My personal google-fu failed me on this one.
I showed myself the door to take a position that I would have never otherwise considered taking, knowing full well how that would look on a resume, but also knowing I didn't want to continue contributing to their bottom line.
(I have a few items on my resume I do not enjoy discussing in an interview, and I've had to add this one to the list: being vague or evasive suggests you're hiding something, but any real explanation just invites the idea that you're the kind of guy who doesn't work well with others. But, such is life.)