The occurrence of altruistic behavior is mediated by mood. Results from studies with children are the most consistent. Happy kids are helpful ones. Sad kids do not engage in pro-social behavior as much. These findings are not so clear as they relate to sad adults.
Research supports all cases.
Some find more pro-social behavior from sad adults, some find less. This cognitive as well as affective bias results in self focused sad people passing on the opportunities to help others. Normally, it would be a big leap of faith to connect a lack of pro-social behavior with the overtly negative rude behavior seen in flame wars. However, social relationships in cyberspace groups are based only on the attention, as explicitly expressed in text, that one member pays to another. Public expressions of agreement with an other's views is the element that creates social cohesion and the feeling of community.