When a candidate starts to head down one path in particular (you know the one - disparaging their current or previous employer), I let them run with it! I want to hear it all (and not because I'm interested in their dirty laundry) - I want to see how far they'll drag their current/former employer or boss through the mud. It tells me a lot about somebody's character when they push the blame button on everyone else and 'dog' the people they worked for (in some cases) for years.
Disparaging comments have no place in an interview and will buy a candidate no points. None. In fact, it’s worse. It always takes away from many of the skills and qualifications they bring to the table. It draws all of my focus to their emotional state and away from their true value. In most cases, the candidate never “get it” and they probably never will. It’s just how they are wired.
Are there exceptions to the rule? Can you discuss a bad work environment in an interview? Yes. But it has to be done in a way that allows the hiring manager to appreciate that you're not just another candidate throwing their former boss or company completely under the bus. It’s not necessary, and it sends out the wrong message (a billboard-sized indicator of the candidate's real DNA). A candidate who says bad things and plays the blame game on their former employer could be giving you a preview of future behavior. Nobody wants to hire a constant complainer – that glass-half-full kind of employee. I say take the high road. Admit that things didn't work out or that the work environment was less than optimal – just stay away from any personal jabs.
There's no place for disparagement in a business setting – especially in a job interview. Always, always take the high road.
