I currently have an employee we will call Juan (not real name). He is usually punctual and works to the best of his ability. Juan is eager to learn but certainly not the sharpest chisel in the box. He has a good attitude but makes stupid mistakes repeatedly because he lacks common sense or is just careless (recently a broken window that cost $600). I've always thought that you can teach all things except work ethic, but my mind is changing. Has anyone had an employee like this? Did they improve?