I really can't think of any.

I went to an interview and, halfway through writing the test, was asked to move to another location. It gave me the strong impression that the interviewee was being treated with very little respect. The HR representative also gave me the impression that I was only invited in to help them meet their recruitment targets—so why ask so many questions? The manager, meanwhile, seemed unwilling to train newcomers but only interested in offering a low salary. So for anyone considering applying, think twice before going.