All these are good (to avoid).

I'd add to the comments to that start a certain way: 'nope' I don't know exactly why but I find this phrasing both dismissive and insulting. Also, all those starting with adverbs, like 'Interestingly,...'. Just say what you got to, I say. It hurts the message if what follows isn't interesting at all. Edit: I'm not trying to insult anyone, I just think this kind of formality where one has to justify, verbally, the existence of ones comment is distracting.

I'd also add the gross over- and misuse of italics for emphasis. I'd almost say it was a phenomenon. Like the amount of emphasis italics is inversely proportional to to commenters knowledge of the subject.