Norway shooter Anders Breivik is the latest accused murderer to flash an eerie, menacing grin. From Charles Manson to Ted Bundy to Osama bin Laden, see the happy faces of evil. Say this about mass murderers—they sure seem to enjoy their work. Accused Oslo gunman Anders Breivik flashed a menacing grin after his arrest that was reminiscent of other killers' smiles. Taking apparent glee in his acts of terror may be a part of the reason his attorney thinks Breivik is "probably" insane. Then again, Breivik may just be imitating the title character from his favorite TV show: Dexter. Scanpix Norway / Reuters Despite a creepy mug shot showing him with a shaved head and a maniacal grin, Jared Loughner, who is accused of shooting Rep. Gabrielle Giffords and killing six others in January 2011, may have a hard time with his insanity defense. While that faraway look in his eyes is awfully convincing, there is evidence that Loughner planned his attack and understood the moral implications of his actions. AP Photo As murderers go, Lee Harvey Oswald's smirk is the Mona Lisa of killer smiles. Was JFK's assassin actually grinning after being arrested for shooting the president, wincing in pain, or is the interpretation in the eye of beholder? Two days later, there was no mistaking the haunting expression on Oswald's face as he cried out after being fatally shot on live television by Jack Ruby. AP Photo One of serial killer Ted Bundy's deadliest weapons was his charm. Following his capture, the handsome murderer, who brutally murdered at least 30 (and possibly 100 or more) women in the 1970s, was always seen laughing or smiling. And Bundy, who was executed in 1989, exhibited another hallmark of a sociopath—no remorse. "Guilt doesn't solve anything, really," he said coldly in 1981. "I guess I am in the enviable position of not having to deal with guilt. There's just no reason for it." AP Photo In addition to the numerous tapes he released mocking the United States following the attacks on 9/11, the smiling face of Osama bin Laden became a symbol of the fact that he had not been brought to justice. But all of that changed on May 1, 2011, when Navy Seal Team Six permanently wiped that grin off his face by shooting bin Laden in the head. Twice. AP Photo After terrorizing New York City in the summer of 1977 with a series of murders, David "Son of Sam" Berkowitz did not look the part of a serial killer. With his nebbishy smile and shy and awkward demeanor, Berkowitz, who is still in prison, hardly fit the image of a Satanic murderer. But some good did come of his case—the so-called Son of Sam law was enacted, prohibiting criminals from profiting from their crimes. AP Photo Though his given name is Very Idham Henyansyah, he is better known as Ryan, the Smiling Serial Killer of Indonesia. Ryan, who faces the death penalty for bludgeoning 11 people and burying 10 of them in his parents' backyard, has basked in his celebrity following his arrest. He has been the subject of a documentary, published a memoir, and even released a pop album while in prison. Stringer Indonesia / Reuters A killer who has a swastika tattooed on his forehead is probably not too concerned about how he will be perceived by the public if he's seen smiling. And for the past four decades, the grinning face and wild eyes of Charles Manson have been the very definition of the word "madman." Eric Risberg / AP Photo For some people, the only thing scarier than serial killers are clowns. And John Wayne Gacy, who murdered 33 boys and young men in the 1970s, was both: Gacy used to work at children's parties and charity events as "Pogo the Clown." (While in prison for his crimes, he even took up painting and frequently created portraits of a smiling Pogo.) In 1994, when Gacy was finally put to death, his defiant last words—“Kiss my ass”—were not exactly cheery, but the signs held up by those who were happy to see him executed seemed to get the last laugh: "No tears for the clown." Sure, dolphins have those adorable smiles, but so does their far more dangerous cousin, the orca. And when marine biologists actually dub them killer whales, why should humans be surprised when they live up to the name? In February 2010, Tilikum, a bull orca at Orlando's SeaWorld, dragged a 40-year-old female trainer under the water at a "Dine With Shamu" performance, drowning her. It was the third such incident Tilikum had been involved with in 20 years, but after some new safety precautions at the park and a yearlong hiatus, he was cleared to perform again. Tilikum can now be seen working alongside his daughter Malia and his grandson Trua. Phelan Ebenhack / AP Photo