Many missing sized blocks. (Mentioned before)
Most gun add-on sounds are garbage.
People constantly hitting on girls, as if they aren't there to build but for you and your selfish desires to have a girlfriend. Give it up, you don't care for them, you care only for yourself you selfish conceited fool, you just want a girlfriend.
Add-ons installed incorrectly. I constantly have to moderate my add-ons folder so it doesn't go over 10 GB.
Racing servers (when there is one) with over 20 downloads (most of them guns) not relating to racing in any way.
Medieval RPGs with guns.
Uzi being more powerful than a minigun.
White undulo rainbow print bricks used to make a rules board.
Admin only doors.
More than 3 admins on a server.
Wrench Events.
Zombie Deathmatch.
Freebuilds with forced minigames.
Wrench on build trust (I changed this on my server.)
Uncleared builds which do not suit the theme.
My biggest hate is when noobs keep the BlockheadXXXX name. Yesterday I saw someone who had kept a blockhead name, his ID was in the early 3000's.
I seen one in the 1000s.