EDIT: For all intents and purposes, if a person says they can predict the future, but does not state their predictions (perhaps by keeping them in a sealed envelope), then there is no prediction. What good is a prediction that goes unsaid? It's garbage. What if I said "I can become invisible just by snapping my fingers, but I'm not going to show you?" Would you believe that too?

EDIT: Here is the thing: psychics cannot see anything special. They have no special powers, and their only special ability is in conning people into thinking they have special powers. Psychics have a lot of tools in their arsenal to help them "predict" things about people. Sometimes they have their subjects fill out a questionnaire, sometimes it's based on personal observations, sometimes it's a combination of many things.
For instance: a person appears to be of Irish-catholic heritage, based on their physical characteristics, their name, and the medallion of a Saint around their neck. Based on that, you can come up with a lot of very-likely names for people who are in their life: Mary, Mary Margaret, Erin, Daniel, Michael, etc. And people who believe in psychics are often forgiving when it comes to failed guesswork. So you say "ok, I'm seeing something about a person with a name that begins with M... M... "
And as the psychic repeats it, this gives the subject the chance to interject with a name by shouting out "Mary?" "michael?" or "Emily?"
There are tons of videos on YouTube exposing fraudulent psychics... and they're all fraudulent, even if they themselves don't realize they've just developed a knack for guessing.