From an author's point of view, what would you consider as negative peer reviewer comments?
When reading reviewer feedback, I generally divide things up into five mental categories (sorted from best to worst):


Praise: It feels really good when a reviewer "gets" a paper.
Little stuff: Anything that can be cleaned up easily, like typos and grammar failures, dropped minus signs, mislabeled figures.
Suggestions for improvement: Things that are legitimate issues, but are reasonable to push off to future work if necessary.
Legitimate complaints:  This is where a reviewer points out actual significant problems with one's work.  If you were unaware of them before, or thought they were less important than the reviewer explains them to be, then this can really sting, but it's a reasonable judgement.
Nasty, unfair reviewer #3: This is the stuff that really burns, when a reviewer seems to have an personal agenda or grudge and is taking it out on your paper.  A recent example I encountered included the phrase: "All the hard questions are systematically discarded."


What's very difficult, as an author, is distinguishing between suggestions for improvement, legitimate complaints, and unfair reviewing.  This is particularly true when things are presented harshly: I find a major difference between directness (which raises a clear issue about the science) and harshness (which might or might not be clear, but is presented with a side-dish of personal attack).

However, especially when it comes to things where you have feelings like "but it's obvious!" or "but we already addressed that!" or "they must not have read the paper carefully!", there is usually a legitimate difference of viewpoint, which it's important to figure out how to overcome. 

That's why I always read feedback more than once, at at least a couple of days separation.  The first reading lets you see how much the review is praise vs. little stuff vs. the other three categories.  At that point, though, you're generally too emotionally involved and reacting (particularly if you got a rejection) to distinguish which category the issues raised by the reviewers actually fall into.  A couple of days distance, though, and I find it much more possible to parse out the different strands of negativity, figuring out which are legitimate, which are unfair, and which are more appropriate to push off to address other papers.