I really do enjoy the built-in bluetooth hands-free system in my car that allows me to talk on the phone through the sound system. However, I have noticed one unusual tendency of mine.
I am in the habit of switching though radio channels via the little button on the steering wheel. I have noticed that when my girlfriend calls and starts yelling at me for some reason (does she need a reason?), I find myself hitting this button to try to change the channel. Alas, to no avail. Every channel is her.