If you are asked "What did you least like about your last job," you want to honestly answer with something that you didn't like. However, it may or may not be the thing that you most disliked.
If, in an office administration job you hated filing and filing will also be part of the next job you are looking for, then telling the interviewer that you most disliked filing might not be your best choice.
Instead think of something that you disliked in your last job that will either not be part of this job at all, or will be a very minor part of the new job.
Also make sure it does not put anyone down. "I disliked the way my previous boss barked orders," would not be an advisable response.
However, I disliked the long commute and the part time hours would be fine, assuming this job is closer to home and full time.
Or, if true, "there was nothing I really disliked about my last job, and I felt I did well in all areas of it, which is why I am applying for this one which appears very similar."
That would be a good answer.
So bear in mind not to opt yourself out of anything by saying you don't like part of the job for which you are applying, and instead see if you can turn it around to tell the employer why you are good for this position.
Here are some more great tips on interviews.
More on Successful Job Interviews: Questions and Answers
(c) Fiona MacKay www.backtoworkcoaching.com