Just a quick review, as I don't see any posted yet and it's a pity, because this show is very good and the lack of publicity that it is getting is not deserved.
I have seen all episodes of the first season and would love if they continued the story, and for that to happen this show needs to get more attention. The writing in this is spot on, really. The humor is often subtle, dark and ironic, and if you enjoy that kind of humor (coming more from the sarcasm of life than, you know, cheap swear words) then you will enjoy this very much.
Characters are also very likable, and I have enjoyed every episode after work as a "treat" to disconnect the mind and laugh. Anyway, I really recommend everyone to check this TV show out if they have the chance, its truly good – check out the pilot online on Youtube and judge by yourself, if you like the first episode you will most likely enjoy the rest.
As for flaws, I think other secondary characters going to the therapy sessions could have been better developed and their stories better fleshed out, I understand that was not the objective of the show but maybe it would have helped to carry the story on, but I get that the story focused more on David than his patients.