Phases

All of my boys have gone through various phases in their lives. 
When Noah was about three he was fascinated with guns, knives, blood, and guts.  I was convinced that he was going to grow up to be a serial killer, but sure enough it was just a phase that he eventually grew out of. 
Last year, Jonah started obsessing over rooms that had open doors.  He had to have every door shut all of the time.  I thought that we were going to have to live with severe OCD for the rest of our lives, but once again it was just a phase.
Now Jonah is the one obsessed with blood and guts; and Micah is the one constantly closing every door in the house.  Sure it is annoying, but I know that it is just a phase. Because of that knowledge, I no longer lay awake at night planning out visits to see my children at the state penitentiary or mental institution.
So what phases have your children gone through?