It's clear that Jon Heder is a controversial comic actor. 'Napoleon Dynamite' was a great favorite among young people, some of them of course, and established immediate cult status, but is dismissed by many. Heder is a comedian who is more than willing to play the fool. His performances are effortless; they just flow out of him naturally. He becomes whatever embodiment of absurdity he's handed, be it a geeky high-schooler ('Dynamite'), a preening skate star ('Blades of Glory'), or a lazy young adult who's turned into an a-hole due to his fear of facing life on his own ('Mama's Boy'). Unfortunately Heder's embodiments are so successful some audience members can't separate the actor from the role, and they turn on him. 'Variety's' stringer critic in the only mainstream review you can still find online says, completely inaccurately, that Heder is simply doing a reprise of his 'Napoleon Dynamite' role in'Mama's Boy.' The consistent panache with which Heder impersonates obnoxious geekiness every time doesn't mean it's the same character. Each of those three has his own quite separate motives and personality.
But like I said, Jon Heder is an acquired taste, one many seem incapable of acquiring. People find Jeffrey's up-front selfishness (again, not meant to be taken seriously) so repugnant, reactions to the whole film become so totally negative right off the bat that comments show a misreading of practically every main character, except maybe Anna Faris' Nora Flanagan. She is a caricature too, but nobody seems to mind or even notice. But like Daniels' Mert, she's nice to Jeffrey until she can no longer be, and Jan (Ms. Keaton) can never be any other way with him -- that is, till tough love finally forces her to ask him to move out.
Actually this is very nice stuff -- deceptively so: viewers seem to mistakenly suspect something much more negative and ugly about to happen, but if you read Jeffrey carefully, his meanness is only skin deep. It's rare that any movie, let alone what appears at first a rather dark comedy, is so full of human decency. After all, even Jeffrey tries to do harm, but winds up not really succeeding. It's because of this prevailing decency that Jeffrey can convincingly come to his senses and become in his turn a good person, like Jan, Mert, Nora, and Seymour.
This is an age-old function of comedy: to reunite people and bring about redemption. Despite a strong tendency revealed on this site to reject this movie and declare it a clinker, it could never be that with a cast of this caliber doing very good work. And it's not a clinker at all, just a low key comedy that, if you tune into it, has some good laughs and leaves you with a good feeling.
Jeffrey, the useless slacker who's living off his mother at 29, is Heder's most darkly conceived character so far. It's essential not to take him too seriously. It's all just a pose, though a pretty sad one, if taken seriously. Otherwise, everyone delivers fine performances, and they play it pretty straight. Ana Faris is a superb comic actress, but she's astonishingly real and natural in her scenes with Jeffrey. Her performance allows us to see that he could be attractive, if he would stop being weird and using people. Diane Keaton also is real and natural as his mother, and Jeff Daniels, a splendid and supple actor in a role that could be made maudlin or a caricature, also turns out to be a good guy, who treats Jeffrey as if he were normal, hoping that he will turn out to be in the end. This is a comedy about redemption. Of course the 'Say Anything'-mimicking ending is a little too easy, but hey, this is a comedy, and a pretty simple one. Eli Wallach's old man tells Jeffrey "I'm 91 f---in' years old": this great, tireless character actor actually is that age in real life. And Wallach has acted in six more movies since this one was made two years ago. What a guy! And overall, what a great cast! And let's not forget to mention the always interesting Mary Kay Place.
This film seems to have been virtually dropped from the Web's records. It was reviewed when it came out briefly in theaters, but now all you can find is a scattering of mediocre and superficial DVD reviews and, because it promises to keep a record of all the films that come out, the one in 'Variety.' Unfortunately the 'Variety' critic, like too many of the Users on this site, did not take a very close look at what he was writing about, and his observations are of very little use. Fortunately there are a few who recognize that this is, though not a great piece of work, a quite entertaining and watchable one, in which good actors give winning, natural performances, and Heder again shows his special fearlessness and ease at embodying a comically repulsive (but underneath not unappealing) young man.