Rugrats
>Season 1
This isn't a bad season but it's pretty rough and lacks the polish because they were still cutting their teeth.
>Season 2
Golden age Rugrats. Your favorite episode is most likely a season 2 episode unless you're a massive contrarian.
>Season 3
Good, better than season 1, but doesn't live up to season 2. They introduce Susie here and, honestly, she's a good addition to the show, but they also barely use her.
>Season 4
The quality of the show takes a dive here. There's a few good episodes here but they're outnumbered by crap.
>Season 5
Continues the downward spiral. There's just about one good episode in this season. This season leads into the movie.
>The Movie
The movie was trash.
>Seasons 6 to 9
Rugrats is absolutely unwatchable post-movie.