Good grades are not a goal...says my professor

I am really confused about this statement. I am taking SNHU-107 and I had to write out three short term goals. My first goal is to get a B or better in all my classes. I was told that that is not a goal, it has to be something different. How can a personal goal academic goal be wrong? I am so confused why getting good grades is not the goal. Can anyone shed light on this for me?