@NobodyReally is spot on with everything he's said in here.
Coming from someone that had minimal knowledge of this affair going into the film (only that du Pont was a paranoid schizophrenic)
, I left with know perceptible insight of any of the characters' motives, no sympathy nor apathy towards anyone involved and just a general lack of understanding of everything (no backgrounds given). We never get the raw, gritty matter of the relationships/illnesses, just some surface building nonsense that really didn't go anywhere. I wasn't expecting something as vivid as '
Clean, Shaven', but this was a poor character study, which not even Carell's amazing performance could save. The final act played out like a
that privilege mommy's boy who wasn't getting the attention he felt he deserved and just randomly went out and picked off Dave for the hell of it.
It's climax was reached by generic anti-social cues rather than a descent from his actual condition.