BMW iDrive - How infuratingly dangerous is that

We have just come back from a 2 week holiday with BMW 3-Series hire car. It was a nice car that did what it was supposed to do except for IDRIVE... what a horrible piece of kit. I was always impressed with the Nokia telephones because I never once had to look at the manual to figure out what I wanted to do, intuitive would be the word... not so the iDrive, after 2 weeks we still hadn't figured out how the passenger could adjust the radio volume!