My wife is exactly the same!!! Drives me crazy! Her old car was a 2007 Corvette Convertible. Had the Dual Zone auto settings. Worked like a champ. Now we have a 2009 Mercedes E-Class with the same thing. When I drive the car, I set it to auto and we are off to the races. When she drives the car and it's too hot, she dials the bloody temp settings down to sub-zero temps and cranks the fan up to "full speed ahead captain"! Then she gets cold, so she turns the heat up to the "I am hotter than the sun" setting. I have tried endlessly, and painlessly, to explain to her that we spend a lot of money for these nice little conveniences and yet she just flat out refuses to use them.
I feel your pain my friend!! It's a battle that we will never, ever win (but you can be damn sure we will keep on fighting the good fight!)