I think it's great that they are not making BoJack "just the douche" character. Backstories help a lot but it's also just about setting up the scene: can people be good in the environment? What are the motivations, challenges, triggers, and obstacles? Who defines happiness?
Letting you stay with me was the best thing I ever did on purpose. I don't think I ever told you that, but I should have. Because you're my best friend, Todd. You know, it's the funniest thing, there is a woman in this restaurant who looks just like you.