If you ask Marc Guggenheim, and people have, he will tell you the first season of DC's Legends of Tomorrow was all about figuring out exactly what they were doing and the type of show it would be. By season two they realized that the bigger and crazier they got, the better the show was. They should be constantly circling the shark, but never actually head up the ramp for the jump. It's a fine line that the got figured out near the end of the second season, and there was no better proof of that then the best episode of 2017: Doomworld.
When it became know that the plan was for the Legends to take on the Legion of Doom and that it would consist of the Reverse-Flash (Matt Letscher), Malcolm Merlyn (John Barrowman), Damien Darhk (Neal McDonough), and Captain Cold (Wentworth Miller)… so many questions popped up. And to the surprise of many, not only did the actually use the name Legion of Doom, but they even gave them a headquarters almost identical to giant, submersible helmet from the old Saturday morning cartoon series. And by the time we got to the penultimate episode of the season that was directed by Mairzee Almas and written by Ray Utarnachitt and Sarah Hernandez, the show had fully embraced the insanity.
Eobard Thawne had re-written history and made the world how he wanted it. The show could've gotten very dark, but instead the comedic beats worked even better. Damien Darhk making a super villain monologue was great, but having Malcolm not only call him on it, but identify it and compliment him on it was brilliant. There were the running gags of Nate's mom's sandwiches being so good and everyone punching Mick Rory when they got their memories back. And the fact we got to see Felicity Smoak (Emily Bett Rickards) in a costume was just the icing on the cake.
Though they don't coin the expression until the third season, Doomworld and the season finale Aruba showed the team living up to their motto: "Sometimes we screw things up for the better." Between the "celebrity" guests, the crazy setups, and then the emotional punches of stuff like losing Stein (Victor Garber) and Jax (Franz Drameh), it shows that Guggenheim and the others have figured out what the show is supposed to be, and Doomworld is the perfect example — which is why it's the show's best episode of 2017.