Most would criticize Doug as formulaic, unoriginal, and all around bad. I watched this show (and it's Disney pimped sequel) for years, and I have to say, it was one of the best cartoons produced during its time; and it still holds up well.
The premise behind the show is simple: Doug is a young boy trying to make it through life, but learning a lot of hard lessons along the way. The difference in the show is just how outlandish the accidents, mishaps, discoveries and general mayhem gets. Despite an amount of predictability (it WAS written for children) the show had great humor that surprised me, given the low age of the target audience. Most of the jokes aren't great repeatable quotations like Family Guy or Futurama's, but they were entertaining (and educational) for us as kids. The Disney sequel had more adult humor and a little more maturity about using a cartoon as social commentary, but the original Nickelodeon production is rife with memorable episodes and characters.
If you don't think Doug's fumblings with Patti or self-indulgent daydreams of Quailman were at all humorous, you don't know Funnie.