It's supposed to be flat! And yes, you probably are drinking it too cold. The nitrogen beers are supposed to be creamy as opposed to carbonated. Have you ever noticed that Guinness is flat? That's not to say it is never carbonated. It is lightly carbonated in the keg (and widget bottle). Take apart a "Guinness" tap and take a look... there is a diffuser that the beer passes through that decarbonates it. It's probably a matter of taste also. Just thinking of a cool, flat, creamy guinness makes my mouth water