Many interview questions aren't what they seem. For example, when interviewers ask, "What don't you like about your current position?" (or, put another way, "Why are you looking for a new job?"), they're looking to gauge your character more than exactly why you want to leave your current position.
That is, interviewers use this question to see how you might talk about your current managers and company. Will you badmouth your managers and employer and come across as someone who complains and lays blame elsewhere and not on yourself? Or will you make your job search about yourself and never blame others?
Of course, you always want to take the latter route, and make your search about yourself.
One reason for this is it sends the message that you'll be someone who takes resonsibility for your work and actions, and aren't a difficult person to work with. Another reason is it shows that you're a positive person. This is extremely important because negative people are incredibly damaging to have on a team. And since so much work these days is completed in teams, teamwork skills are essential. In interviews, you always want to be stressing how well you work in teams, citing past successful experiences of working on teams whenever you can.
As for what a good answer to this question might look like, the first thing you should do is cite the things you like about your current job (even if that wasn't part of the question). Cite several specific things if you can. And, ideally, you'll cite things that you'll be doing in your new role (the one you're interviewing for). You might say that you appreciate that you've been able to do X, Y, and Z, and improve in them as well. You might also say things about your current employer's culture and work environment that you like and that might be similar at your new firm (if you're hired).
Then, after you've cited a few positives (which makes you sound like a positive person), you can cite some of the things (or thing) that might be lacking in your current position. But be careful here. As mentioned previously, you don't want to make it about the company's shortcomings or your managers' shortcomings in any way.
A good, safe, common answer here is to say something like you want to continue to challenge yourself, and in the role that you're in now, you've gone as far as you can, and now you would like to push yourself further, learn more, challenge yourself further, improve your skills and experiences while helping a team succeed.
And then here is where you might mention the duties of the role you're interviewing for and the attributes of the company you're interviewing with that most interest you and excite you. Although this wasn't exactly asked of you, it was implied, and taking this route in your answer will reiterate your positivity, as well as your interest in the position.
As a final note, there can be instances when interviewers push you a bit beyond this question, asking further questions about your current employer. Perhaps the company you're interviewing with is a direct competitor and they are interested in what your company is doing right or wrong. Whatever the case may be, and whatever the question may be, keep it in your mind to never speak negatively about your current job, manager, or employer. Even if it might seem like your interviewer is on your side, chances are you're being tested. So keep your comments clean and positive.
Recruiters and interviewers will often throw out questions that are designed to test a candidate's ability to think on their feet, and ask them to make a case for something they care about on the fly. In doing so, they're looking to assess how well you can make an impromptu presentation, and also to get a sense of how deeply you think about issues in the world around you.
“New hire’s remorse”—at least under this name—is a recent phenomenon that we broached last week. Also called “shift shock,” it arises when an employee regrets taking a job because it isn’t the right fit or is completely different from what was expected.