Joy just doesn't work.
David O. Russell tries to use their preferred cast in yet another story about a dysfunctional family which drags down the main character and how this character, in opposition to her own family and any other coming difficulty, overcomes everything and leads to success.
We have already watched similar stories in "The Fighter" and "Silver Linings Playbook" and, although weirdly, in those movies it worked, but not in this one any more.
Specially, the ending seems abruptly rushed and truncated and the "Citizen Kane" moment is quite childish and obvious.