What irritates you about co-workers?

That I have any.

That would be a very wrong answer, so don't obey that instinct. Don't be flippant if they ask what irritates you about patrons, since that one, or some variation may also be coming up in your interview.

Your answer could end up revealing personal flaws. You reveal that you are uptight about some minor character flaw or laziness which makes you seem like a nit picker. You could also try to dodge with, oh, I love everybody, hearts and flowers, want to exchange bracelets? But you're going to get that little tsk, which means, we're on to you. And you did reveal a flaw: you avoid conflict and just swallow your frustrations instead of resolving them.

You could say something like this:

I've been very lucky to have worked with supportive and helpful professionals, but there are always minor irritants. For example, a former co-worker would often change deadlines, moving up the dates for projects, sometimes without apparent reason. These decisions made it difficult to deliver on time and to provide my best work. However, I usually found that if I discussed it with her that I would usually find out a legitimate reason for the hastened delivery and that we could work out some time around another project.

And look at that: you identified a problem, dealt with it like an adult and sounded reasonable.

If you tend to brush off annoyances, or don't keep a grudge book, you could read Maureen Roger's post, Throwing at the Batter, to find a brief list of aggravations that colleagues can throw at us. Don't just pick one and make up some creative speech. More than likely you have encountered these behaviors, even from normally rational people. Explain it, name no names, describe how you dealt with it and ask for the next pitch from the interviewer.

Brought to you from David Grant's list of 50 Most Common Interview Questions