The big problem here is in the dialog. Most of what is being said makes no sense, and the characters react seemingly at random to the events around them. Anger, happiness, mistrust, trust, love, hate; they're all thrown around as if the director was throwing a dice while writing the script, to determine what would happen next. Since nothing adds up or goes anywhere, the viewer is left trying to piece things together themselves. And I don't mean that in a good way.
The talented but apparently clueless actors who signed up to film this horror show of a script seem like they've realized their mistake mid-production, and most just phone it in. Wasting Paul Rudd and Jack Nicholson like this should be punishable by .... well, something!
On top of all this, the movie is two whole hours long, for absolutely no reason at all. And despite the length, it ends too sudden and leaves the viewer feeling cheated. One smile (Rudd slams his head against a table in a humorous fashion) is all I mustered.
Not just a waste of talent then, but also of your time. Steer clear.