My biggest pet peeve with Slashdot is that there is no "-1, Factually Incorrect" moderation. When I have moderation points I frequently have to use "Overrated" to fill that niche.
There are not a lot of times, but I have seen a comment that is simply wrong be moderated up (oftentimes a groupthink assumption that turns out to be incorrect).
I find the moderation system one of the best on the Internet. I wish when people had moderation Slashdot would ignore their preferences and instead show comments at "-1, Newest First" to avoid older, higher moderated comments from simply getting moderated even higher at the expense of newer comments that have not had a chance to get moderated up.
But that is just me.
And you should listen to me because I have a four-digit UID, damnit! And get off my lawn!