Most hated structures/rooms
Thought about this topic before I stopped being so prolific here, but I came across one that gives me nightmares. It wasn't quite so bad in the arena as it was in the anti-gravity levels, but it was still bad. It took me many lives and a few days to deal with this monstrosity in the anti-gravity levels. This thing held up by the balloons in the middle of the room.
Along the lines of worst bosses, worst chests and most hated pigs. Be interested in seeing what others have problems with, if any care to share.