What's the best way to deal with an irrationally angry parent?

uming I don't move out soon, what's the best way to deal with an irrationally angry parent? My parent is so angry all the time and nags me so much, I don't even take them seriously anymore. I'm not mean, do what they say, and show complete deference, but my parent remains in a state of constant rage. What's the best way to deal with it?