Moody

Being in a bad mood both improves your memory and your critical thinking skills. Which makes evolutionary sense, if you think of being in a bad mood as being a reflection of environmental stress and danger.

People in a positive mood such as happiness were shown under experimental conditions to have relatively unreliable memories, and show poorer judgement and critical thinking skills. By contrast, those who experienced a negative mood such as sadness were shown to provide more reliable eyewitnesses accounts and exercise superior thinking and communication skills.
In one experiment, researchers at the Sydney-based University of New South Wales school of psychology put different subjects in a positive (happy) or negative (sad) mood state and tested the accuracy of their recall of a staged eyewitness event such as a bag snatch. “The results showed that eyewitness accounts of people in a negative mood are more likely to be accurate compared to those in a positive mood state,” says Professor Forgas.
“It shows that our recollection of past events are more likely to be contaminated by irrelevant information when we are in a positive mood. A positive mood is likely to trigger less careful thinking strategies.”

(via BoingBoing)