Gervais' aim - it seems to me - was to take the audience with him without compromising the unlikeability of his character, and to plausibly 'romance' Tea Leoni, at least in theory (they never make physical contact of any kind) without compromising his pudgy ordinariness. I think that's a fairly interesting challenge, embedded in a mainstream film. In that respect perhaps a bit like As Good As It Gets, where Jack Nicholson's character never actually gets very nice.
If you fancy a light comedy, which doesn't treat you like an idiot, and gives you a nice warm feeling, this will do quite nicely.