The humor is essentially dark for a cartoon and sophisticated. But at the same time, being a cartoon gives the writers more freedom than in a normal sitcom. It always pushes the line that, despite human failings, the Simpsons are really decent people.
“I can't say that I haven't done some bad acting in my time. I have. Usually that involves what we actors call 'indicating,' when you twirl your mustache.”
“Music was our wife, and we loved her. And we stayed with her, and we clothed her, and we put diamond rings on her hands.”