Mostly anything madness/blood is to my disliking. Only ones I've ever enjoyed playing was zone contol. And even those I don't play. The worst map I've played was Halo madness. Human side was way overpowered. But that's typical in madness maps, rigging or unbalance...
Any kind of map that is rigged for a certain player only.
I thought the worst map I played was a zombie hotel map in which the Hotel security are rigged as hell, since it had about 25 goliaths at each of the entrances. Mainly the ones that are bad are madness, since people keep rigging them for their favorite person/character.