Liu, Sub, Ermac, Reptile's d3's because they're amazing and all have accompanying fast comboable(EDIT: except for Liu) OH's with good range that they can just fucking throw out for free at random and you just have to pray you guess the right time to block or give up and eat d3 until they get tired or you have meter and a gap to armor.
So damn annoying, I don't know why NRS would provide these two tools at the same time on a character, it should be one or the other but not both.
Erron's overhead and Scorpions jump kick(I swear i've never beaten a single Scorpion air-to-air no matter who I use, and when they hit you they get a full combo no matter where they hit you in the jump arc) are both serious pains in the ass as well.