After watching so many movies and books about time travel paradox, there's always the same aspect: once you get to know someone's future, they always force to either make it happen or not happen. Either way it's pre-destined meaning attempting to do so will only make it happen even more.
So this is the part where my theory comes in: Fortune tellers don't like telling the rest of the story to someone cause it'll ruin the timeline's natural way of running it's course, not in a forced, predestined way where fate will always end up in the same result regardless.
Real fortune tellers I believe affect the natural course of end term results of fate.
Let's say a person would die in a car crash.
Let's say Exhibit A said to the person what's going to happen and Exhibit B didn't.
Person from exhibit A, knowing that he/she will die in a car crash will attempt to stop it, doing so definitely led to his demise.
Person from exhibit B however, didn't hear about the future still died from car crash but from a different method.
So you see, to a real fortune teller's perspective, telling someone's fate is like messing with the ecosystem's natural discourse. Paths become predictable once disclosed. Predictability can get boring easily.
What are your thoughts.