Fire!

This comes from a friend of Barry Ritzholtz at The Big Picture:

When a fireman sees a house on fire, he sounds an alarm, dons his turnout gear, bravely rescues the occupants and puts out the fire.

When an investment banker sees a house on fire, he quietly sells the burning house short, uses the proceeds to buy a larger house for himself and, when someone suggests that his taxes be raised to help the homeless, he rails against the dangers of socialism.