Are you a Ricky Gervais fan?
If the answer to that is "NO", then why are you even bothering to read this?
If the answer to that is "YES", then so am I.
While I can see where Gervais' act can become tedious for those that bemoan his existence, it doesn't bother me one jot, and probably if it hadn't have been for Gervais, I wouldn't have bothered going to see this flick. I could say something similar of Ghost Town (which was actually quite good for a watch) - Lying is good for a watch, but beyond that I'm not entirely sure.
The conviction of the plot is fine, but the conviction of the comedy is a bit lacking. It's a gentle comedy, with a strong concept to it. If there had been more guffaws then polite chuckles from the audience, then I feel it would have been a stronger film all-round.
That said, there are times in the film which really give a punch - one scene at a death bed, for instance, is very powerful and was tough going - plus it demonstrated Gervais' genuine talent underneath all these ear-shattering laughter and self-deprecation (a similar scene can be found in the confessional Big Brother scene in the Extras Christmas Special). It tempts immoral acts - if it had been real life, you just know the one liar in the world would take full advantage of it, but as this is a film (rated PG-13 too) he never really goes too far, and always turns away at the brink of anything becoming too immoral.
He'll gladly rob a bank (essentially, and more than once) through his lying skill, but he avoids going the distance with a woman he tricks into having sex with him (lest the world end, in his words).
Had this been Rated R, I do wonder if the comedy would have had the room to breathe that was really necessary, but who knows eh?
Good for a watch, particularly for Gervais fans, but if you can't stand his "pudgy, snub-nosed" antics, then steer clear.