Crappy and unacceptable: "I have always been very happy with my performance. I work hard, prepare, and it pays off. This is why I had the highest sales last quarter."

This sounds great in theory, and I know the candidate feels like they nailed the question, but unfortunately this fails. It doesn't answer the question and doesn't give me the example of when someone worked hard to improve.

Answer with Example: "it is actually rare when I am really happy with my performance. I feel like I am always trying to improve. In my personal life I really like to golf / bowl / fish /knit/ you fill in the blank. When I first started 4 years ago, I shot a 100. I knew that this wasn't going to be acceptable so initially I just made it a point to practice at the golf range 3 times a week. As I progressed and watched others, I got videos, read magazines and asked my friends for help. About a year in, I signed up for some lessons. They were expensive but they were the best investment I could make. I now have a much better score and am really proud of what I have accomplished. At my last job, I wasn't very good at running the forklift. I cleared it with the manager if I could get my good friend to work with me after work and just practice lifting pallets. For about a week, we worked on different things. Backing around a corner, stacking pallets so they are straight. Moving one pile to another spot backwards for an hour a day after work. It paid off. I am now one of the most efficient operators of the forklift and my shift supervisor has me train everyone. I am proud of this."