Most of the Japanese cartoon art is usually three and two dimensional and you will find the use of bright colors is always in constant use and help create a montage of various color use. The cartoons are able to look life like because of the use of the colors which help in creating a more realistic look at human emotion. This way we are able to tell if the cartoon is angry or annoyed, by the red cheeks and also if they are sad or sick they usually turn different colors or more pale than usual.
However the colors are not the only thing that the Japanese artist uses to denote emotion. The use of the large western like eyes is also used quite frequently and many times I have always wondered why the use of western characters, have become a big theme in most of the Japanese animated movies and series.
I guess its because the whole world looks to the west as the main super power countries and it is easier to use them as characters in the animated movies.