In fairness I love the series it's based on, and if it's not to your taste, I doubt the movie will be. Though in equal fairness, given what the series is -- truly-horrible interviews with celebrities -- this is a movie that could have been awful. However, thin though the plot is (Zach and his team need to drive across the country to Los Angeles and must do 10 shows before getting there with a deadline of two weeks at 9 AM), they keep the story moving and overload the whole film with snippets of maybe a couple dozen truly-horrible interviews with celebrities, and it's fun to see who is going to pop-up next -- David Letterman, Benedict Cumberbatch, Matthew McConaughey (in a particularly hilarious sequence), Brie Larson, Jon Hamm, Rashida Jones, and on and on, including a recurring role by Will Ferrell who co-founded "Funny or Die" which produced the original Between Two Ferns shows and repeats his "Funny or Die" connection here.
But instead, let's go back to Jon Hamm who was in one of very first episodes they did for the Internet.
(Side Note: from the outtakes during the end credits, the sense I get is that although there is a screenplay to the movie, by Scott Aukerman who also directed, when the interviews specifically were done the celebrities had no idea what was going to be asked -- though I suspect were at least forewarned of the general area so that they could be somewhat prepared with answers.)