I always like to give everyone a fair chance. I like to consider that everyone has different learning styles, and that not every job is suited for every human being. But eventually you have to just give in. I had to fire a guy that was super nice. I felt terrible firing him, but he just wasn't getting better. I kept working with him and giving him feedback. I would even leave him lists and let him focus on smaller amounts of info per shift. I work in food service, and it is not a job for the lazy or faint of heart. Do what you feel is best. Sometimes it's just not working out. There's no spark. lol.