In my time on the internet, I've seen pretty much every cartoon character I've ever heard of and a lot I've never heard of and some I only heard of after having seen in crudely drawn pornography. Simpsons seems to be one perverts really have trouble with getting right and most often look like the wall scribblings of a crazy person from a movie. The DVDs have character sheets and even some how to draw guides. It takes a bit of getting used to but The Simpsons style is very very easy to learn, Matt Groening isn't that good at drawing. There's some pretty hot Simpsons characters, Marge can get it, and don't even get me going on Mindy but it seems like every person willing to draw them naked us an absolute weirdo who also can't draw. Rule 34s generally kinda run a gamut of art quality, but you never ever see a Simpsons character on model
I think it comes from a lack of understanding of realistic anatomy. (Insert Miyazaki quote here). Basically, if someone only learns how to draw from other drawings, it will always look "off" and the less like regular human anatomy it is the more "off" it will look. You could think of realistic proportions as the "rules" of drawing, you need to understand them in order to break them.
Just throwing it out there. 
In my time on the internet, I've seen pretty much every cartoon character I've ever heard of and a lot I've never heard of and some I only heard of after having seen in crudely drawn pornography. Simpsons seems to be one perverts really have trouble with getting right and most often look like the wall scribblings of a crazy person from a movie. The DVDs have character sheets and even some how to draw guides. It takes a bit of getting used to but The Simpsons style is very very easy to learn, Matt Groening isn't that good at drawing. There's some pretty hot Simpsons characters, Marge can get it, and don't even get me going on Mindy but it seems like every person willing to draw them naked us an absolute weirdo who also can't draw. Rule 34s generally kinda run a gamut of art quality, but you never ever see a Simpsons character on model
I think it comes from a lack of understanding of realistic anatomy. (Insert Miyazaki quote here). Basically, if someone only learns how to draw from other drawings, it will always look "off" and the less like regular human anatomy it is the more "off" it will look. You could think of realistic proportions as the "rules" of drawing, you need to understand them in order to break them.