Often, it's to show that even the most mundane objects can have a 'bad' side. It helps teach kids that not everything is as it seems and adds an element of creativity to the story. Also, it could be used to make the story more humorous and engaging.
Maybe it's for adding a funny or unexpected twist. Making something ordinary like a trash can the bad guy creates surprise and entertainment.
Sometimes, in some cartoons, Hercules can be shown in a negative light, depending on the story's plot and the creators' vision.
Maybe because rats have a bad reputation in real life. So, in cartoons, they are easily made into villains for that stereotype.
Bad kids in cartoons might be there to add drama or make the story more interesting. It also gives an opportunity to show how good behavior can overcome the negative influence of the bad ones.
Maybe it's because of his controversial policies and actions that some people find disagreeable.
Sometimes, in certain cartoons, Robin Hood can be portrayed with negative traits, but it's not a common depiction.
Maybe it's because alligators have that fierce look and sharp teeth, which makes them seem scary and suitable for the role of a villain in cartoons.
Well, it could be for making the plot more interesting. Maybe the dog has some negative traits or makes bad choices that lead to it being the bad guy. Or it could be part of a moral lesson to show that not everything is as it seems.
It could be to create a contrast or add an element of surprise. By having an ugly voice for a guy in a cartoon, it catches the audience's attention and makes the story more interesting. Also, it might help in developing a unique character personality.
Well, maybe it's because it makes for more interesting and funny storylines. A grumpy dog can create all sorts of comical situations.
Well, it could be to add some unexpected twists and make the story more interesting. Sometimes, showing a not-so-perfect Christmas makes it more relatable.