Interviewers might be looking for red flag behavior that's caused problems in your current position, how you speak about your company, and if your shift is merely a matter of convenience. Your knee-jerk reaction to a question like this might lead you down a path of trivial explanations that are turnoffs to prospective employers (like their proximity to your house), or worse, dogging on your current company. Try focusing on your desire to continue growing and developing in your field, specifying how the position you're interviewing for would help accomplish those objectives.
