One of the most negative habits is in my opinion the failure to read a comment charitably (to make an effort to interpret it in the best possible light). Instead, people often tend to misread or miserunderstand what's being said, only to use the opportunity to write a "correction" based on that false impression. A worse flavor of the same problem is a misunderstanding that is then used to justify outrage or personal…
This is like the phenomenon examined in this 2005 paper: Egocentrism Over E-Mail: Can We Communicate as Well as We Think?[1]
From the abstract:
> Without the benefit of paralinguistic cues such as gesture, emphasis, and intonation, it can be difficult to convey emotion and tone over electronic mail. [...] this limitation is often underappreciated, such that people tend to believe that they can communicate over e-mail more effectively than they actually can.
When we read a HN comment negatively, we should second guess our interpretation of it before we reply. We may not have perceived it the way the author intended.
Likewise when writing comments, we should ask ourselves if our wording might be received more negatively than we realize.
[1] http://faculty.chicagobooth.edu/nicholas.epley/krugeretal05....