What is common knowledge in your field but shocks outsiders?

More than half the CO₂ emissions of the industrial age have been dumped into the atmosphere since 1990.

@davidho (IT Professional); Hackers don't typically succeed because they have insane technical skills and expensive equipment. They succeed because Linda in Accounting has a lack of critical-thinking skills and/or is careless.
Saturday Morning Breakfast Cereal - 2012-02-20

Saturday Morning Breakfast Cereal - 2012-02-20