Being hyperaware of my surroundings is one reason that I can't stand insects or dogs. They both move around so much, in a disjointed, disconcerting fashion, and in ways you can't easily predict. I just want to... make them stop moving. I hate how I can't control them, and they're not guided by any kind of purpose of their own. I also tend to get freaked out when I hear unexpected noises.
So, for me, being N doesn't mean that I'm not aware of sensory information, it just means that I don't find it that interesting, and that I usually experience it in a negative way because it distracts me or makes me uncomfortable.