I responded as candidly as I could, which was that I didn't like working with hostile/jerky people, and that if I had to find a common theme amongst all of the jobs I'd left (which weren't a ton, but enough to create a small sample pool), they all included personality conflicts with people. The overarching theme of all the questions I was asked during my interview really focused on culture and cohesion with the other workers, so the question was interesting but not out of left field.