Not all of them. There are cases where the details are so specific that it's difficult to chalk it up to coincidence. Consider a story where a fortune teller told a man he would find a lost item in a red - painted building. The man had lost his grandfather's watch. Months later, he was helping at a community center (a red - painted building) and found the watch in a drawer there. There could be some unknown forces at work or perhaps the fortune teller has some intuition that defies explanation.
I don't think they are all coincidences. There are countless real stories where fortune tellers have made accurate predictions. Some might argue that they are just good at reading people and making educated guesses. But in many cases, like when a fortune teller predicted that a couple would have twins (and they did), it seems more than just a lucky guess. There may be something more mysterious going on that we don't fully understand yet.