It could be that the faded eyes in cartoons are meant to give the character a unique or mysterious appearance. Sometimes, it's just an artistic experimentation gone a bit off.
Maybe it's because of the way they're drawn - with sharp lines or dark colors that give a creepy effect.
It could be to show that the character is lost in thought or deep in reflection. Sometimes, this expression conveys a sense of shyness or modesty too.
Often, cartoon eyes looking mad are used to convey a sense of frustration or conflict. It helps make the character's feelings more obvious and engaging for the viewer. Also, it might be a stylistic choice to make the character stand out.
Maybe it's because of a difficult situation the character is facing. The worried eyes show their concern or fear.
Often, when cartoon eyes are angry, it's to show a character's strong emotion. It could be because of something that happened in the story or to emphasize their personality. The choice of colors and shading can also contribute to that angry look.
Sometimes, cartoon eyes look crazy to make the character stand out or add a sense of humor or surprise. It's a creative choice by the animator or illustrator to catch the viewer's attention.
Maybe it's to show the character's strong emotions or to create a certain mood in the cartoon.
Well, it could be to convey a character's mood or reaction. Sometimes the context or situation in the cartoon makes the eyes look annoyed to show frustration or dissatisfaction.
Maybe it's because of a threatening situation in the cartoon's story.
It could be because of the way they're drawn. Maybe the artist wanted to convey a certain emotion or character trait.