[JoshTriplett]

On the positive side, you might have someone complaining bitterly because the codebase they worked on had twelve different implementations of string/buffer classes and was resistant to any attempt to unify them. Or someone complaining that they pushed for continuous integration and never checking in anything that broke the build, but people kept bypassing code review and breaking things anyway. Or that there was a standard release process in place for hotfixes, but some Nth-level manager handling a customer escalation would demand a one-off release for their customer without going through the normal process. A well-explained complaint like that would suggest that the interviewee pushes for good processes and solid engineering practices.

On the negative side, you might have someone complaining at length about a bikeshed issue (see http://blue.bikeshed.com/), or complaining about processes they had to follow that sound reasonable to you (for instance, "one change per commit", or "don't break the build"). Or someone complaining bitterly that they don't get to use technologies invented five minutes ago.

It's a lot easier to get information about what people stand for and care about by finding out what they fight against.