From Sonic News Network:

Described as having "a strong sense of justice"but is young and somewhat immature. He feels anger and joy intensely and loudly, but his sadness is silent and hardly, if ever, marked by tears. He lets his rage control him and cheerfully remarks on the things that make him happy, but hardly says a word in his sadness, though it is visible to everyone. However, though he may feel sad, he never gives in to despair.