Because otherwise they would be unable to track movement and move the cursor in the computer screen.
Because it had a hole in the middle.
Kinder Surprise
Because of the Taliban (say it out loud)
One is a group of cunning little runts.... the other is a group of running little C
Sir.
A. There is cheese in front of the mouse.
I'm having a movement"
He wanted to check his e-mail.
Because your foot would go right through the computer screen!