It may have its funny moments, but having seen the whole first season, I think that calling Girls a comedy isn't really selling it right. It exists sort of at the line between Comedy and Drama, wistfully drifting between the two, as opposed to most other comedy/drama blends which usually have clearly defined comic and dramatic elements/scenes. Rather than doing sharp swerves between the two, Girls somehow manages to be both simultaneously.
I don't like it.
I think the main problem with it is that I don't really find it funny. But unlike almost every other comedy out there, I have the hardest time figuring where exactly I'm supposed to laugh. There are frequently moments where I see the characters acting quirky or saying things that fit their personalities, and I don't really think much of it, apart from "yeah, that's something this character would do". Then I see a list of "Top Laugh-Out Loud Girls Moments" and they'll include all these odd character moments that I didn't realize I was supposed to laugh at. I guess that I can honestly say that I don't get the humor of Girls.
So without laughing at it, the only way for me to like this is to appreciate the dramatic elements, right? Well, we have a problem here too. Mainly, I hate almost all the characters. With the possible exception of Shoshanna and Charlie, none of these characters have any good qualities. They are all egotistical, selfish, and on the part of Hannah, REALLY pretentious. Now, shows have had unpleasant characters before and done great (Seinfeld, Curb Your Enthusiasm, Archer), so that isn't a dealbreaker in and of itself. The problem is that Girls expects me to care about these characters. They have all these moments that are clearly trying to make me go "Awww, poor characters! They lead such hard lives!" The shows that I previously mentioned expected me to laugh at their asshole characters; Girls wants me to relate with their asshole characters.
The first goal of any comedy is to make the audience laugh. Comedies can choose to direct audience laughter at heavy subjects, but laughter is still the main objective. The first goal of Girls isn't laughter; it's trying to make me feel/think. It just so happens that the people making the show are naturally funny, so it bleeds out into their work. That's the vibe I get from watching Girls, and it isn't a good one.