why do my parents disrespect me when I act friendly, but respect me when I act not human?

whenever I act friendly or trusting to my parents, they verbally and emotionally abuse me by telling me to go to hell, trying to control my finances and acting irrationally by yelling for no justifiable reason because they THINK that I am saying something to hurt them when I have good and kind intentions. whenever I act not human in the household (not smiling, no emotion, no talking, not looking at them directly), they respect me and don't bother me. I recently told them I am moving out, and ever since they have been acting nicer, except one parent who told me good riddance and that I should get out. why do they do this?