The End of Innocence

Normally, I dislike knee-jerk expressions of optimism. But I realize they're good for the children.
So when I'm with my two-year-old son, Zebulon, I find myself quoting Bob the Builder (or "Bobadenden'' as Zeb calls him).
"Can we build it?'' I'll call excitedly. "Can we fix it?''
His answer is always, "Yesa Can.''
Until the other day.
When I asked him at lunchtime if we could build it, he irritably shouted, "No!''