I assign people who confuse you so that you can't tell what they mean by their actions. They do something that seems to mean one thing, but then they tell you something completely contradictory the next time you see them. (The best part about this is that I have told this particular friend of mine that he has been assigned to Mordor several times, so he knows it when he bugs me.)
To Mordor with pointless homework assignments. What my social studies teacher could possibly think I'll learn by writing down definitions of terms such as 'density', 'right of way', and 'water table' is beyond me.
Also, classes where homework isn't checked every day, but instead all the assignments for the unit are checked in the form of a quiz at the end of a unit. This can lead to major procrastination and is just a general pain.
The book
Ethan frome also belongs in Mordor.
**Spoiler** Any book where characters decide to commit suicide by sledding into a tree is just plain dumb.
When you get the vague uncomfortable feeling that your friend's parents see you as rather odd and look down on you because your family isn't quite as 'normal' as theirs is.
That should never happen outside of Mordor.
Edit: All the people on my robotics team two years ago who didn't want to name our robot
Oliphaunt, but then whined that they didn't like the name we ended up with (
Epsilon) and complained that nobody had suggested any other names. I'm still annoyed about that more than a year and a half later.
Losing/misplacing things.