Fans of the CW's Arrowverse — which includes shows like Arrow and The Flash — may not have much experience with Legends of Tomorrow. The show began in 2016, and brought together a selection of minor characters from the Arrowverse and sent them travelling through time and space to thwart the schemes of an immortal warlord. You know, basic superhero stuff. The whole premise was that the characters selected to take part in the mission were secretly chosen because their lives had no impact on the timeline; they were losers, in other words.
The first season was decent. Fairly standard for the CW, a mostly serious (but comic-booky) drama with a fun cast and safe humour. I wasn't a big fan, but at the time my superhero phase was in full swing, so there was no question of abandoning the show. I'd forced myself to sit through episode after episode of Oliver Queen's angsty antics, I could tolerate this too. It might have been the basicness of the show that put people off. It did alright, ratings-wise, but nowhere near as close as its sister shows like The Flash. All in all, a decent season that fleshed out some of the less developed characters.
Now from season 2 onwards, that's when the good stuff started kicking in. See because there wasn't a whole lot riding on the success of the show — the characters were all minor and the time travel meant the main continuity of the Arrowverse would never be affected — the CW assigned it a much tighter budget than their main properties. The upside of all this meant that the creators essentially stopped caring about making their show tonally consistent with the rest of the universe.
In a word, they started freestyling.
First of all they stopped taking themselves seriously. One of my biggest criticisms of the mainlines shows is that they just try way too hard to have gravitas. It's great when they nail strong emotional moments but come on, your main character is a guy with a bow and arrow, you need to acknowledge how ridiculous that is. Legends does not shy away from how silly it is. My favourite scene in season 2 is when Martin Stein, a grumpy old professor who functions as the constant voice of reason, must distract a room full of scientists so his teammates can infiltrate a moonbase. Panicking, with time running out and tension rising, he looks frantically around the room, then stops, opens his mouth and starts singing the 'Banana Boat Song'. The whole room stares at him. He gets really into it too, it's a joy to watch, and it comes completely out of left field. This is the same season that the audience discovers the resident violent meathead of the team — Mick Rory A.K.A Heatwave — secretly writes erotic literature.
It's phenomenally entertaining watching the team interact with each other. They give such a positive vibe, always ready to emotionally support each other. They may not necessarily be the most effective squad, but they make up for it by being the most chaotic one. Every new addition fits perfectly into the group. I love how often a forgettable character from The Flash or Arrow gets banished to Legends of Tomorrow, as if it's a punishment for being unpopular. These characters will invariably become fan favourites after the transfer.
Damien Dahrk, for example, is a mediocre antagonist from season 4 of Arrow who returns to life during season 3 of Legends and becomes an absolute icon. He's revived during an 1800s blood ritual and when he wakes up, he massacres a room full of time police whilst dancing to Mark Morrison's 'Return of the Mack'. Dahrk is a million times more charismatic in Legends, you can tell Neil McDonough had much more fun portraying the character within the quirky, tongue-in-cheek tone of Legends. He's sassy, unhinged, and genuinely sympathetic by the end.
And that's my main point about why DC's Legends of Tomorrow is the best show in the Arrowverse. The main properties don't always live up to their dramatic tone, but Legends is always fun. It keeps finding ways to get more ridiculous without losing the investment of the audience. They break the fourth wall and do wacky, gimmick episodes. They throw in massive, game-changing elements like the discovery of Hell like it's nothing. Legends is a treasure trove of comic-book nonsense, if you're put off by the constant high-stakes and emotional conflict of the rest of the CW, I'd highly recommend giving it a try.