@geraltitude: I'm not saying he's complex - I'm just saying that what they're aiming for is to make the character an ineffectual loner who tries really hard to have people fuck off so he's not hurt by them. Which is why he refuses to get to know Marty for three months, feeds him his bullshit nihilism, gets wasted before coming to the family dinner, is furious at Maggie for using him for revenge sex.
I mean, the show's main theme is lying, or rather that lying and presenting it as truth doesn't make it true. Marty lies that he's a family man, Rust lies that he's a cop to "bear witness", Maggie lies that she played no part in their falling out, they both lie that Ledoux died in a Hollywood gun fight, everyone tries to live the lie that the case was over with Ledoux.
Not to mention that Rust goes on his wildest tangents when he's talking with the two detectives in 2012 and we already know that he manipulated them into checking what they have on the case, going as far as drinking a six pack during the interview so it will be inadmissable.