SAN DIEGO (CBS 8) - It was a chaotic scene on the streets of San Francisco Wednesday night following the Giants' World Series win.
Fan celebrations turning violent is a common occurrence, and we looked into what's behind this destructive behavior.
The San Francisco Giants revelers went all night long lighting fires, and two people were shot, both non-fatal. Forty people were arrested, nine police cars were damaged and several businesses got tagged with graffiti. Officers armored in riot gear were also assaulted.
"The Giants won, so why do we have violence in San Francisco?" Psychologist Dr. Michael Lardon said.
Lardon says no matter the sport -- like we saw when the Lakers win the NBA championship in 2010 against the Celtics -- celebrating a win is primal behavior that goes back to the Roman days.
"When your team wins, it's as if you won victory for survival," he said.
And alcohol intensifies the victory.
"You take that tremendous feeling of victory from this war and then you throw in some alcohol, as psychiatrists say, is the elixir of the super ego," Lardon said.
Sport riots can even get be deadly, like in Egypt in 2012 when al-Masry beat al-Ahly in a soccer match, and 72 people were killed.
This year, University of Arizona students threw fireworks at police cars when they lost to Wisconsin.
"Careful, you can make an irreparable mistake that changes the course of your life," Lardon said.