"Defensive pessimists," she says, "prepare for a situation by setting low expectations for themselves, then follow up with a very detailed assessment of everything that may go wrong." Once they've imagined the full range of bad outcomes, they start figuring out how they'll handle them, and that gives them a sense of control.
http://www.oprah.com/spirit/Defensive-Pessimism-How-Negative-Thinking-Can-Pay-Off
That's why I hate it when people tell me to stop being pessimistic. What's so bad about planning for possible failure?
