It's a show about confronting your past, accepting loss, and growing past your old self.
I'm fascinated by the lukewarm response this show's received. It feels so refreshing to have a show a) tell you what it's going to do and then b) do it. It spends the first three episodes establishing the characters and the conceit, and then follows through on everything a narrative is supposed to follow through on.
Every major character has a "core trauma" that they must confront and move past. They ingest pills which put them into dreamlike states where they can fuse their trauma with mythological encounters, which lets them face their problems head on in a more abstract sense. Just about to the letter how Joseph Campbell explained the purpose of myths and legends.
Even the non-dreaming characters face larger-than-life scenarios they must overcome in order to overcome their own core problems. Without spoiling it, Dr. Mantleray (Justin Theroux) has a hilarious and way over the top problem that he confronts in an equally ridiculous manner.
Which reminds me of another facet of this show: it's not afraid to let you (or make you) laugh. Unlike Bojack's Flip McVicker, who says before his premier, "This show contains no intentional humor."
It's a tonic for people tired of Prestige TV. The "it gets good" syndrome, where we have to wait a whole season for any kind of "payoff" to hours of wheel-spinning, setup, and dissolution. I'm tired of mysterious characters doing weird things and waiting eight episodes to find out why. Plot is not a puzzle. I want to know the characters, to care about them, to know in clear terms what they want and watch them struggle to achieve that. Which, I think, Maniac delivers on.