I only watched the first episode - some people claim the show improved somewhat by the time it was canceled a couple of episodes later - but wow, that first episode was pretty disastrous.
Written by Amy Sherman-Palladino, whose work on the Gilmore Girls was brilliant, and starring talented "indie queen" Parker Posey, on paper this was going to be great. But it wasn't. Posey's performance is shrill and brittle; she acts the whole episode as though she has realized she is in a bomb and hopes that if she talks loud enough and fast enough people won't notice. And while the writing isn't terrible, it's not especially funny.
Which leads us to the laugh track. There is perhaps nothing so destructive to low-key witticisms than a boisterous laugh track. Sherman-Palladino is not a sitcom writer, and trying to persuade the public that she is by dropping huge laughs on every wry remark or deprecating comment just makes the show seem to be full of unfunny jokes. I had a similar reaction of Sports Night, another show where dry wit combined with loud laughs created nothing but dissonance (although my reaction to that show wasn't nearly as negative as my reaction to Jezebel James).
So, if Posey were calmer and the laugh track were gone, would the show have been good? Maybe. I would be curious to see Jezebel James sans laugh track with Posey replaced by, say, Lauren Graham. My gut feeling is that it still wouldn't have worked - that Amy just couldn't find the rhythm of the half-hour sitcom - but I'm not sure. All I am sure of is that the network executive who insisted the show have a laugh track should have been demoted to a janitorial position.