Jim Carrey's Yes Man struck me as an awful waste of a terrific premise.

Far from the retread of the Liar Liar gimmick that some people claim, Yes Man's central conceit really resonates, and gets at a simple but profound truth: saying "no" to opportunities is safer and easier, but saying "yes" is more rewarding and fun. Literally having the main character start saying "yes" to everything is not my preferred way of tackling this issue, but it could easily work as a goofy, absurdist approach. Jim Carrey's track record may be bruised, but the actor is still a national treasure. And Peyton Reed's filmography contains some films that managed to be thoughtful despite their staunchly populist aims.

What an unpleasant surprise, then, to see a film so terminally mired in the worst Hollywood comedy conventions. It's hard to be meaningful or even sincere when everything is hideously distorted to fit the confines of hoary old formulas, complete with scenes that don't fit, but which a movie like this simply must contain. Yes Man winds up shrill, manic and unpleasant (albeit sporadically funny) when it should have been breezy, earnest and simple.

Examples. The idea is that Carrey's Carl Allen is the type of guy who declines opportunities all the time, to his own detriment. There is any number of ways to depict this so that it makes sense. Instead, the movie opts to have him literally say no, to everything, all the time – sometimes before a question is even asked -- which is good for a montage, but not a character. Then there's the film's inexplicable decision to add a supernatural karmic dimension to his eventual "yes" experiment – whenever he says no, he is literally hurting himself, in that he immediately falls down the stairs and/or is bitten by a dog. "Yes" leads Carl to a romance with the lovely Zooey Deschanel, but I wonder if we're in for the inevitable scene where she discovers that he's with her not because he wants to be but because he made a covenant to say "yes" (see also: because it was his job, because he made a bet...).

The interesting thing is that Yes Man was "inspired by" a book that purports to be a memoir of sorts, found in the "biography" section of your local bookstore. Here, I thought, I might get the story I wanted from the film. And to some extent I did. If you were attracted to Yes Man's premise but didn't like the film – or refused to see it – I can issue the book by Danny Wallace a cautious recommendation.

I say cautious because, despite its pretensions to "true story" status, the book is not a great deal more realistic than the movie, and in some ways gets just as carried away. (Wallace pretty much gives away the game in the preface, where he notes that he moved things around a bit, but "for your own good. I don't want you falling asleep on me.") For one thing, it's so snarky as to be disingenuous – one of its hooks is that, as part of his experiment, Wallace says "yes" even to Nigerian email scams, and so he carries on and on for pages quasi-sarcastically pretending that he thinks some sultan who knew his father really does want to give him $40 million. (Positive thinking, you see.)

On the other hand, Wallace never pretends that "yes" has supernatural qualities. He paints himself at the beginning of the story as a sullen, routine-bound shut in, not a "no"-shouting caricature. His romance with "Lizzie" (the counterpart to Deschanel's Allison) ends sweetly, without a phony dramatic confrontation about his "yes" obligations. And he is sincere and realistic about the power of "yes" and the benefits and limits of his experiment.

The book is very funny, though in a droll British way that might have made it an ideal project for Ricky Gervais instead of Jim Carrey. (That could have been fantastic.) It's pretty easy to see why its high concept was refashioned into an ultra-mainstream, wacky Jim Carrey extravaganza, but the result was disappointing for anyone who hoped that the movie would take "yes" even a little bit seriously. Danny Wallace's book is maybe 80 pages too long, but it's much more thoughtful, and a lot more fun.