
Bangor University's School of Psychology has spent a good deal of time
researching the reason why so much more energy seems channeled into anger instead of happiness, and why angry people get more attention than the positive ones. For an example, just look to the comments section of most websites: You'll generally see a lot of positivity there at first, but little by little, it will all start to go wrong. Insulting comments start to crop up, and they are responded to--again insultingly--until the whole thing devolves into a giant pantie-fight over minor technicalities and personal opinions.

"It's 'there,' not "their,' and there's no "the" in front of "Watchmen" and RRRAARGHAAAAAAHHHH!!! I AM THE GOD OF HELLFIRE!!!"
But it's not entirely the Internet's fault. When the Bangor scientists studied the section of the brain that responds to angry, happy or neutral faces, they found something interesting: This area is also tied closely to areas of the brain associated with survival instincts--like your fight or flight reflexes. When you detect anger in your vicinity, your facial recognition center suddenly lights, allowing you to better detect possible threats. Or, as one researcher puts it, "The ability to remember who is angry may have been of evolutionary importance in enabling us to respond to a threat situation. Remembering who's happy is less important as it bears no relation to our own immediate safety."
As a side effect of this--our brains being wired to pay more attention to anger--any pissed off dickhead who is otherwise irrelevant, will still seem much more important to you than a reasonable person who should otherwise take priority. It's not necessarily the case that there is more negativity, it's just that you pay more attention to it. So basically, the concept that "all you need is love" has officially been disproven by our very genetics. Sorry, hippies, but the brain has spoken: Impending punches are just flat out more important than Eskimo kisses.

Researchers have
recently identified something in the human brain that they are calling the 'Hate Circuit.' Presumably located right next to the 'Awesome Processor' and just behind the 'Titties Motherboard,' the hate circuit consists of two subcortical areas of the brain that work in concert to create the emotional response of hatred in human beings. The Wellcome Laboratory of Neurobiology at UCL discovered this circuit in a study they conducted, wherein the brains of participants were scanned as they were shown pictures of people they personally hated, interspersed with other familiar, but otherwise neutral acquaintances.
When the subjects were shown pictures of the hated subject, heretofore known as the Motherfucker Control, two areas called the putamen and the insular cortex kicked into high gear. These areas are also associated with motor planning--so when the participants saw the Motherfucker Control, their brains immediately began preparing to act.