Why is it?

Why is it that when people are in there car's driving somewhere they will do thing they would do outside of there car's?
Say a lane is about to end and you have seen signs for this for about a miles or little more. Why do some people get in the others lane and others do not?
Would you cut in front of someone to get in line somewhere else? 
And why is it okay to do in your car?
I'm just asking here cause I'm dumbfounded on this issue, people will pull more stuff in their cars than say a store or mall. I've come up with somethings I feel are why some do, and other don't. Lets call this the Badger road test. In other words I'm calling some people out to make them think about the actions they take in their automobiles, would you pull that same crap walking down and street. I believe most people would not. Now don't get me wrong some people would cause this, cause some people are just out and out assholes.
The me first at any cost, they would do straight to your face, they don't care. I'm good with that cause you know what you are and you deal with it. It's the nice people who turn into some out of there mind driver is the ones I'm talking about. You know you'll see someone out of their car nice personable, maybe smiling. Saying "Hi how are you today!" and then they get behind the wheel. Forget about it two inches off your back bumper, banging on the steering wheel wanting you to go faster. You have no place to go, cars are all around you, they can't see that we're all moving along, and yet they need to go faster.
Here is the way I see and maybe I'm wrong, if I have open road in front of me. That doesn't mean I can go as fast as you want. There is still a speed limit posted, and if it's just a plain old two or four lane I'm only doing five maybe ten miles over. Most of the time right around the speed limit.
I feel that its a me first type of thing going around, not sure where this came about. Maybe our lives are just more ramped up, with things. Have very little or even no time to ourselves? Is this it between all of the other activates in our lives we have lost any time for other people? Is this more like peoples way of eat, or be eaten. If I make home fifteen seconds before my neighbor I win, he's slow. He's the wildebeest that got eaten by the lion, and I lived to eat the sweet savanna grasses. It doesn't work that way does it, or does it? I'm the one who's wrong, the one who is looking at this backwards.
I'm not sure it is funny to watch cause people in there cars will do silly things......