I like antagonists that are complete nutcases, but only if they're done well. it's a lot more difficult to make an energetic character intimidating, but they can be a lot of fun just as a sort of unstoppable force of chaos. I find it a lot more interesting than another big guy who doesn't say much or a shadowy manipulator. just a dickhead who does whatever they want with no concern for others. these sorts of characters don't mesh well with having followers or henchmen though, they're more suited to working alone or with an equally insane spouse that they're uncomfortably intimate with. they can also contrast with a more traditional and organized villain.