Too much of the first episode is to give the audience a taste of how bitter her life is, and they succeed a bit too much, since most of the episode felt awful to watch, but... the origin story ends with the episode, and she bites for the first time, and that's what I think most people watching the show expect.
In comparison, Dexter kills someone in the first 5 minutes, this is the oposite, we are drag trough her horrible existence as much as possible, so much that some people will tune out... but I think there is a pay off and a potential behind hi, she had teeth now, and everything will change because of that... Yes... her moral compass is off... as many pointed out... but is not the point... all that pressure is finally released in a boom... we will see if she matures or devolves, anyway, annoying life, big bang ending, potential for the series, we will see.