We just talked about strengths, are there any areas you would like to improve in?

The interviewer knows that an individual with a realistic assessment of strengths and weaknesses is likely to be more balanced and productive. In addition, recognizing weaknesses demonstrates a willingness to be teachable, rather than the kind of person who thinks that they know everything. Share with the hiring manager an area you feel you might improve in but don't belabor the point. Be positive about your desire to work on the deficiencies you have.