I wrote a short story called "Shooting Goliath" as a realistic story of what happened to me when I fell off a waterfall. BUT I also have a scene in my time travel adventure where my main character jumps off a waterfall to catch someone else's attention. Now I KNOW that's fiction... because I'm scared of heights, but I have had the experience that makes that section believable. I have a character in that book that lost their spouse after 30 years, which has also happened to me. My story is based on the concept you can't help others if you can't help yourself. Every character has doubts and fears to overcome before they can complete their assignments. I focus on what I do know, not on what I don't.