You could for example start talking about how you thought something was a colossal failure only to realize looking back that it was an incredible learning experience and how sometimes the only way to learn big lessons like that is by trying the experiment. And how it's only a failure if you stop. But you kept going so it wasn't really a failure.

Honestly we should probably take a page out of politicians' or media trained people's playbooks and not even answer the question as asked but relentlessly steer towards what you really want to talk about.