south park has been the most consistently funny of the cartoon sitcoms, imho. what are they in the 11th or 12th season...obviously not every ep. is a knockout but SP is good for 3-4 knockout shows per season...its the way they make it. doing it the week before, that way it will always stay fresh & be relevant & timely with the jokes.
family guy doesnt have staying power. its not funny when you re-watch it, b/c inane sight gags are only funny so long.
there were some good eps in season 16 of simpsons...the one where bart gets really fat was funny. there are a couple other ones i liked from that season. i havent kept up all that well recently. if you dont like it, dont watch it. problem will take care of itself.