There has been a request to "count" the admins that we have encountered at Wikipedia, who may at one time or another have chaffed non-admin editors. Some of the most difficult actions that I've seen from admins are those who get into a conflict with a non-admin editor, then block the non-admin editor, then erase or censor the history of the discussion, then chastise the non-admin editor in private or off-Wikipedia correspondence.
Some of the admins I have seen fulfill all or most of these distasteful actions are:
User:Pschemp ( http://en.wikipedia.org/w/index.php?title=User:Travb&diff=next&oldid...) -- this admin has been very active in the past with blocking IP addresses and such. But, I feel a line was crossed when discussion between two OTHER users was censored because it posed a situation whose implications Pschemp didn't like.
User:JzG (http://en.wikipedia.org/w/index.php?title=User_talk:JzG&diff=prev&ol... ) -- my interpretation is that this admin was dishonest in his edit summary when he deleted an article from Wikipedia, by saying "article created by a banned user while banned". The date of article creation was June 2005, about 15 months before any banning related to this company took place. So, there is an untruth in the public record ( http://en.wikipedia.org/w/index.php?title=Special:Log/delete&page=ICR/In...), but when attention is called to it, that comment gets deleted by a "Troll B Gon" device with unlimited comedic value and an equally boundless disdain for civility.
User:Lucky 6.9 ( http://en.wikipedia.org/w/index.php?title=Special:Log/delete&page=User_t...) -- this guy was quite famous for making edits and dishing out User blocks, then when properly-formatted complaints would be leveled to the administrative heirarchy, he would try to censor out the complaints before anyone was able to take action. It looks like he self-destructed before the ArbCom or anyone higher could desysop him.
Now, those are merely three off the top of my head, just from my experience. I will venture a guess that the WikiEN-l list will now work to discredit me personally, because I brought these examples to the group's attention. What will THAT process then say about the cultural health of the admin community?