because they keep missing the gears and keep grabbing
the passengers p�nis!
seriously though,id think its got something to do with having their head filled up with too many things such as,''am i going to be late to pick up the kids,what shall i cook for dinner tonight,have i still got all that ironing,washing up and hoovering to do when i get home,and i hope that c@nt knobby has'nt rifled through my purse to steal money as usual for alcohol so he can sit all day in front of the computer unwashed in his own filth talking to his g@y womanless lowlife friend legend on answerbank!'' thats my theory!