Messages sent to artists wanting them to work for free

An enraging gallery features more than 50 screenshots and messages showing people asking artists to do free work and sometimes getting angry and nasty when denied. It's good for your portfolio! You're getting paid in exposure! Why do artists only care about money? Most are taken from the excellent For Exposure twitter account, where more beauties are regularly posted. And then there's this classic from The Oatmeal.