Rob Walling - Personality Traits of the Best Software Developers:

"No one anticipates a catastrophic system failure by looking on the bright side. The best developers I know are experts at finding points of failure. You'll often hear them quipping "What could possibly go wrong?" after someone makes a suggestion to handle a critical data transfer via nightly FTP over a dial-up connection. The best developers anticipate headaches that other developers never think of, and do everything within their power to avoid them."