When an interviewer asks about self-improvement, it shows they seek to hire someone who takes initiative and wants to grow. Here's a sample response:

"I have been reading Dave Ramsey to help me improve my personal finances. So far I have learned ways to be more intentional with my spending and investing. I want to be responsible and make wise choices so that I can retire without the stress of finances hanging over me."

This example relates specifically to the finance industry, which would score you extra points in an interview! Rather than talking about Eckhart Tolle and your journey to enlightenment, think about a goal you are working on that relates directly to the field in which you are applying. Focus less on any weakness you want to improve, and more so on the steps or actions you are taking to improve.