While I know that some people didn't like very much this episode, personally I think that it was brilliant. It does a very interesting job with the classical plot of one outsider trying to take the place of somebody else, by pretending to be nice and trustworthy.
Kinda like "The Hand that Rocks the Craddle", but better.
Also, every single joke from this episode were effective and hilarious, with a perfect timing. In this episode we also learn some interesting "facts" about Rigby (Such as his greatest fear, for example) Doug was a great villain, being one of the most interesting antagonist from the entire series. He also made a very good point near the end of the episode (Which unfortunately is ignored by Rigby)
Anyway, this was a very funny and well made, which is also completely underrated, in my opinion.
Kinda like "The Hand that Rocks the Craddle", but better.
Also, every single joke from this episode were effective and hilarious, with a perfect timing. In this episode we also learn some interesting "facts" about Rigby (Such as his greatest fear, for example) Doug was a great villain, being one of the most interesting antagonist from the entire series. He also made a very good point near the end of the episode (Which unfortunately is ignored by Rigby)
Anyway, this was a very funny and well made, which is also completely underrated, in my opinion.