i hate having a long compile and forgetting a player start.
i also hate caulking. i used to map for cs and there was no such thing as caulk. i force myself to do it everywhere possible, but i always forget to start the buildings and stuff from caulk.
i always get pissed when u want to click something in 2d view but u get the brushes above it.
my least favorite by far is making stuff look realistic. all the littel things that make stuff go from game to real life are a hassel, especially becasue they're usually really small.
There are only 10 kinds of people in this world; those who know what binary is, and those who don't.