dander up

Said of one who is annoyed or angry. Don't get your dander up with me—I'm just trying have a conversation here. I know I got my dander up a bit last night, so I understand why you're avoiding me. He knew I was nervous about asking Mary out, so it really got my dander up when he strolled on by and started teasing me about it.

dander up

To be angry. “Dander” is the particles of hair that break off an animal's hair (humans call it “dandruff” when it happens to us). “To get your dander up” calls to mind the hair that stands up on the nape of an enraged dog's neck. Another meaning of the word is the ferment used in making molasses; getting your dander up in that context suggests that your anger is rising the way yeast or any other leavening or fermenting agent does.