Fearless said:
Of course researchers are like anyone else, but is this really common?
It happens.
Example: A friend of mine used to work in a field where "everyone" tried to publish their important results in a particular journal. The problem was that the field was fairly small (a particular application of a particular type of material) and the journal only used a few referees and they were all working in the field in question.
The problem was that one referees used was also the leader of a group that kept getting results that were different from what everyone else was getting (which later turned out to be because of the way they were growing their films). Unfortunately he was also convinced that his group was right.
So, on a couple of occasions my friend was unlucky and ended up with this guy as the referee. In both cases the papers were rejected because the referee claimed the results where not "consistent with known results" (i.e. his own) saying there must be something wrong with how the samples had been prepared etc.
It was very to easy to identify the referee because he would also refer to several of his own papers in the report.
Anyway, on both occasions my friend (or rather his supervisor, this was when my friend was a PhD student) wrote a letter to the editor and asked for a new referee. The papers where then accepted and published.
This is an extreme case, but I can think of a couple of other examples as well.
So yes, it does happen. Hence, my point is that if you are convinced that the paper was rejected for some "unfair" reason you should definitely ask the editor for a new referee.