Replying to Dumb Ass Teachers

So i wanna know how the fuck a school can hire some of these people, the other day i was in drawing (had to take it for credits) and my teacher (a Crazy ass old bitch named biondo) is like Rob, "u know your failing right" and im like "No" shes like "you are", im like "i just turned in my upside down drawing and you said i would be passing" shes like "you didn't turn that in" Even thought i just did 2 fuckin dayz ago!  so i start to bitch and she says "if you ague with me theres gonna be consequences, yelling at me" so i kept bitchin and she gave me 2 hours of detention.  Wtf, I turned my shit in, she said i didn't and i get fucked over.  How do these crazy fucks get jobs.