I agree with Cotton.
What about if people have yellow, orange or red karma? How do you think they might feel? They may feel embarrased and ashamed.
And also, karma dosen't mean anything to do with how nice a person you are. You might have been given negative karma because you make posts that say "hi!", which isn't mean, but just SPAMmy.
Anyway, if I must, my karma is green. It dosen't mean anything, though!