John Lennon said (or borrowed), "Life happens when you're making other plans."
As life story writers, we can take full advantage of the truth in this statement by focusing on two genres: humor and suspense. In essence, they both hinge on a single element: surprise.
For the story to work, however, the surprise cannot be completely unsuspected. Instead, it should be hinted at obliquely as you go along. We shouldn't guess it, but we should experience the mouth-watering-like pleasure of smelling something good just around the corner. Your hints in the story should be specific enough to keep us from feeling misled but vague enough that we don't guess either.
Thankfully, life is full of surprises. Pick a suspenseful or humorous moment and write about it.