I have been through this on interview and my best experiences are:

• never lie about previous workplaces.
• always keep being polite, you can tell the truth about previous workplaces, keep your opinion civilized. Don't start a neverending complaining.
• never mention exact people, you can tell that you had conflicts woth co-workers.
• try to be constructive. If your work was bad at previous place, say how do you imagine a better one.

Let's see clearly, if you leave a workplace, there are reasons, if you are lucky, it is just that you wanted to learn more, see more, get more experience. But there are occasions when the previous place wasn't good for you.

I never experienced any bad reactions when I said:

I left my first workplace because over the years sadly few guys got in charge who's management skills weren't sufficient, so we didn't get any project for awhile, I wanted to work and use my skills, and it wasn't a good place for that anymore.

or an another

That workplace was consuming too much of my time, the job itself was interesting and new, but we really did have to work too much overtime like usually 12 hours daily. Sadly that place suffered of a transition between being a garage project and small company, and it really missed a middle management.

I expect respect for my choices, finding a job is a two side game: you are looking for a good job, and your future employer looking for an honest and well working employee.

If your previous job was really horrible, try to form a valid, rational opinion about it inside you, keep it simple, and tell. Instead of saying it was horrible, point out few major issues which were dealbreaking for you.

I have been through this on interview and my best experiences are:

• never lie about previous workplaces.
• always keep being polite, you can tell the truth about previous workplaces, keep your opinion civilized. Don't start a never-ending complaining.
• never mention exact people, you can tell that you had conflicts with co-workers.
• try to be constructive. If your work was bad at previous place, say how do you imagine a better one.

Let's see clearly, if you leave a workplace, there are reasons, if you are lucky, it is just that you wanted to learn more, see more, get more experience. But there are occasions when the previous place wasn't good for you.

I never experienced any bad reactions when I said:

I left my first workplace because over the years sadly few guys got in charge who's management skills weren't sufficient, so we didn't get any project for awhile, I wanted to work and use my skills, and it wasn't a good place for that any more.

or an another

That workplace was consuming too much of my time, the job itself was interesting and new, but we really did have to work too much overtime like usually 12 hours daily. Sadly that place suffered of a transition between being a garage project and small company, and it really missed a middle management.

I expect respect for my choices, finding a job is a two side game: you are looking for a good job, and your future employer looking for an honest and well working employee.

If your previous job was really horrible, try to form a valid, rational opinion about it inside you, keep it simple, and tell. Instead of saying it was horrible, point out few major issues which were dealbreaking for you.