We all know that being the "nice guy" isn't a very good idea. People new to the game, however, often take this advice overboard and become jerks.
I went through the same thing. I would use too much sarcasm, teasing, and negs, and I would come off as an asshole. I was just reminded of this the other day because a friend of mine was gaming this girl for a couple weeks. He K closed and was doing well, but he overdid it with the sarcasm and negs.
I think stuff like that is fine in the approach to show that your not interested. In the comfort stage, however, it can be damaging.
So the moral of the story is...be a little nicer once you get into the comfort stage.
Agree? Disagree? Feel free to correct me

I find that when I have reached the comfort stage and continue to neg the HB will sometimes become uncomfortable with the conversation. Then again some HBs hold their own and neg back showing that they are comfortable with the situation. I have found that you have to read the situation and make judgments based on how she is reacting to you as you reach the comfort stage. If she is leaning in push her back and say something like "hey now, I know I smell amazing but you're invading my bubble." This should be playful of course but it shouldn't be so much a neg. If she is into you she might say, for example, "but your bubble is better than mine". What you do from there is up to you...


*EDIT*: and by the way, yes I agree with what you said. Moral of the story is be a little nicer once you reach the comfort state.