Mixed Signals?!

My big problem comes from my parents giving me mixed signals.

"You are not helping me with your inepitude. Get out of the way and go serve yourself..."

turns into

"This really pisses me off when you sit down an eat when I've worked my as of all day."

and

"You should learn to drive."

turns into

"No, I won't take you driving, even though an adult is required in the car for you to drive legally."

WHAT THE FUCK. DIDN'T YOU JUST TELL ME POINT A?! WHY ARE YOU COMPLAINING WHY I DO SOMETHING WHEN YOU JUST TOLD ME TO DO IT?

I realize the first one was a hidden invitation for me to be patient and be nice for the family, but I had already extended an invitation, and they turned it down. No good when you explicitly tell me to do something and it's even harder to tell your sarcasm than if you posted the same damn thing on the internet.

Because of mixed signals, I still don't drive even as I approach my second year of college, and I'm deathly afraid of approaching my parents with big news/decisions. I feel like I have to ask them a question or present something at JUST the right time because I have no idea how they'll react at another time.

But enough of my personal angst. Do you get mixed signals from people and how do you deal with them?

Jam it back in, in the dark.