Scott: the fact that he doesn't care about the risks. It scares you when he's out, searching for dangerous villains that are out for his head. You can't do anything about it and it makes you overall frustrated and upset.
Stiles: he has no time for you. It's the supernatural world before you. Always. It's so exhausting when you plan something and it has to be cancelled because Scott and the gang come first in your relationship.
Derek: his bad boy attitude. He can be sweet, loving and overall adorable but in an instant, he can be come a cold hearted bitch. He doesn't purposely do it but it still makes you want to rage on him when he does happen to be rude and very disrespectful.
Isaac: when he gets too rambunctious. Isaac is always up for an adventure and doesn't care if this could end up killing him. He wants to live freely in the moment and it makes you a nervous wreck.