Merkel in an interview with Der Spiegel
"Merkel: Until November of last year, I thought extensively about whether I should run again. In no way did I view the decision as self-evident, and concluded that, to the degree it is possible to determine such a thing, I have the necessary strength and that I am still curious - about people and about how life and the country are changing, and about the challenges that politics present. I think that is decisive, that you don't think you already know everything."
Read the interview here.
Not only for a Chancellor but for an author, for everybody, this is decisive: that you don't think you already know everything.