Because otherwise they would be unable to track movement and move the cursor in the computer screen.
Batman: my parents Riddler: no its a bowling ball! I-im so sorry!
She answered "About an inch".
Covers tracks
I don't know, I lose track of time when I have an erection.
A mouse going on vacation.
Mickey Mouse. What duck has two legs
His vision was based on movements.
I'm having a movement
Because your foot would go right through the computer screen!
He wanted to check his e-mail.