Thinking is the quickest route to destruction
 for thinking leads to realization
 and realization can shatter the soul

"Do not dwell on the past."  This is sound advice from my history professor and I suggest you listen.  I didn't and now I'm hurting.  Don't think about the atrocities that children experienced in My Lai during the war in Vietnam.  Don't think about how the Nazis treated the Jews in concentration camps, sorting their clothes, stockpiling shoes, heaping naked bodies outside.  Don't think about all the millions of people who have died without knowing Christ.  It might destroy you.