Cause you get josled all around, and when you (use to) have to fight the paper map with it's many creases, and settle the kids down, or keep them occupied, and play games with them, and get up early to leave, and only have a limited position you can set in for hours on end, you get tired!! When my husband was in the military and we traveled a lot, one time I told him going on 10 hours in the car, if he didn't stop soon, I was writing a note to hold up to the window, "we were being kidnapped". Back then it was funny and of course, it was a joke, but I know it's not a funny joke today. Anyway.............................