Major incidents, such as 9/11 and the Virginia Tech and Columbine shootings, seemed to be isolated tragedies, but headlines in the last year have been getting increasingly more grim with this string of events: Chardon, Ohio high school shooting, Feb. 27, 2012; Aurora, Colo. shooting, July 20, 2012; Newtown, Conn. Sandy Hook Elementary school shooting, Dec. 14, 2012; Houston, Texas college stabbing, April 9; Boston Marathon...