I just rewatched S07E16 A Woman's Work Is With A Gun and Dina Hale (Patricia Hindy) is seriously crazy and not in a good way. She's a dope addict who shot her pusher in the opening scene and decides to pull off a series of tour bus holdups with two friends she met at Oahu Women's Center. The first one goes off with no problem and emboldens them to try more. The second she shoots out the windows and the third one of the accomplices and a police officer are killed. Of course in the end, five-O captures her and her surviving accomplice in an almost comedic scene where McGarrett lifts her completely off the floor and shoves her into Danno and both of them into a wall.
So we know Five-O has had its share of psychotic bad guys, does Dina rank on your list of the craziest bad guy? Why or why not? Who else can you think of who is completely nutty giving McGarrett and his crew grief?