I was always pretty lucky with having supervisors and colleagues who were mostly polite and friendly and even if there was need for some clear words, they kept a high level of professionalism. I just know a lot of stories from colleagues in other groups about their not-so-controlled co-workers or supervisors.
Maybe this is why the following incident got me started thinking about the topic, even though it was not an obviously bad situation. I'm not sure if I'm in favor of any of the two people involved or if I just dislike the whole incident:
The professor wrote an abstract for an upcoming conference and circled it to all the co-authors on the list and asked for comments. The topic includes parts of a PhD students work (but not solely), so the student is on the authors list as well. However, the student didn't like the context in which his work was put and the whole abstract wasn't specific enough for him. He found strong words to express his criticism, but that was still ok. But at the end of his email he added a re-written version of the professors abstract. I thought that was odd and out of line. The professor addressed the students criticism very objective in an email, but no changes were made to the abstract.
In their next meeting, the student apologized and explained that he didn't want to appear rude and he had thought, that re-writing the abstract would speed up / assist in the finalization of it. So he had realized that his email was somewhat out of line and had the guts to apologize for it. The process seemed to head towards a happy ending.
But then the professor pulled out some old story, where the student had reacted in a rude way against him a few years back. And concluded that he was not surprised but had nearly expected some kind of not appropriate behavior of the student.
Again, I thought that was odd and out of line. Maybe the professor thought it was necessary to re-install the hierarchy and he certainly was more crossed about the situation than he wanted to be. But if measured in rudeness, I'd say they are even now.