Who knew watching sick people could be so funny!
"Flu Season" is a perfect example of a Parks and Rec episode that works so well because the characters are put in situations where they are forced to not act themselves. We see many characters like April, Leslie, and Chris, who have been affected by the flue epidemic that is swarming Pawnee, and it is their lack of health where they hilariously act abnormal. The writers are smartly able to use these situations for comedic purposes. It asserts superiority for us viewers, very similarly to the way we can laugh at someone who is falling down. The funniest character to see in this condition is Rob Lowe's Chris Traeger, who up this point has been basically a perfect guy with absolutely no flaws.
This episode is as tightly written as they come. Basically every scene and almost every single line is hilarious. I would say this is probably one of the most quotable episodes in the series. Some great ones include: "You had me at Meat Tornado;" "Stop...Pooping;" "Good evening, everyone. I'm Leslie Monster. And this is Nightline;" And my personal favorite: "Leslie, I typed your symptoms into the thing up here and it says you could have network connectivity problems." (Completely improvised by Chris Pratt himself). This episode has a perfect mesh of incredible writing and incredible performances, and the results are comedy at its best.
There is literally too many great things I can say about this episode, it would be impossible to mention all of it just in this review. (I sounded like Chris Traeger just then). We have a brilliant main storyline that brings out new sides to these already great characters. A just as good side-plot with Andy Dwyer and Ron Swanson who form an unlikely bond with each other. And even another funny plot with Tom interacting with older gentleman at a spa. Because of all these reasons, I would put this episode towards the top among the best episodes of the series. I could literally right an entire essay on the brilliance of the episode (there I go again), but I will allow you to watch it yourself so you can form your own thoughts and opinions on the episode and see if you agree or disagree with me.
Quick side note: A majority of the scenes take place at the hospital, and its worth noting just how important Ann's character is in this episode. She is basically the "straight man" in all these comedy scenes who is tasked to maintain composure with characters who are acting insane. Without her, this episode would not have worked nearly as well.