Perhaps the boy is allergic to the ingredients in the cake or has been told not to have it. That could be why he's looking away.
It could be that the boy has just had too much cake recently and doesn't want any more right now. So he looks away to avoid temptation.
It could be that the boy has some dietary restrictions or is saving the cake for later. Also, he might have just had a big meal before and doesn't have room for it now.
Maybe it saw something that scared it or made it uncomfortable.
It could be that he's avoiding something he doesn't want to face or is simply looking in a different direction for no particular reason. Maybe the artist wanted to create a sense of mystery.
Maybe she's distracted by something off-screen.
Maybe it's distracted by something or just in a mood. Sometimes characters in cartoons do random things for no obvious reason.
The cartoon boy could be slinking away because he's in trouble or doesn't want to be seen. It could also be that he's playing a game and this is part of his strategy.
It could be that he's playing a game and running away is part of it. Or perhaps he's avoiding something or someone that makes him feel uncomfortable.
Maybe he's up to some mischief or trying to avoid getting caught for something he did.
It could be that he's observing something interesting on the ground, or perhaps he's just lost in thought while up there.
The cartoon person might be confused and looking away because they encountered a problem they have no clue how to solve. Maybe they also witnessed something that contradicted their expectations.