curses

so with curses you eiter scale the curses -% resist ...

never do you have a cast do nothing, because you didn't want to take the time to balance it.

+1

Or, at the very least, put some huge unmissable graphics over the heads of the not-cursed-because-gem-too-low target -- like PoE1 has a padlock above things which are curse immune when you curse them. It's not clear when you have a skill that literally progresses from working to not doing anything but taking your resource.