Proper use volume control?

Certain songs have certain volume levels that seem just right in my opinion. I use the volume adjusting mechanism to find that.

Direct connection between 2v source and amp would tear up your speaker drivers at some point in the music, proper funtion of a volume control is to attenuate the signal.

"Correct" volume level is something I have come to realize through multichannel recordings. A solo part,for example a violin, is usually located in the center channel. I know how loud a real violin can play, and I set the volume accordingly. However, when I do this I often find that the rest of the orchestra is too soft. The mix engineers figure that since the soloist gets the big bucks, he or she should be emphasized. In my system I can easily adjust the relative volume of the center vs the other channels. This is not so easy with a two-channel system.

Now that the volume control whys (not wise) have been brought to light, can someone please explain why there has to be a gas pedals on cars?