Most TV shows don't reward you for paying attention.
'The Simpsons' from the very beginning was based on our memories of brash '60s sitcoms - you had a main title theme that was bombastic and grabbed your attention - and when you look at TV shows of the 1970s and '80s, things got very mild and toned down and... obsequious.
The really great thing about having two TV shows going on at the same time is that I can go to one and say that I have to go and visit the other, and then I can just go home, and they don't know.
We did 'The Simpsons Movie,' which took almost four years; it was the same people that do the TV show, and it just killed us. So that's why there hasn't been a second movie. But I imagine if the show ever does go off the air, they'll start doing movies.
'The Simpsons' is an especially collaborative show.