What does fortune-telling mean by seeing before but not seeing after _ fortune-telling?

Fortune-teller said that seeing before and not seeing after.

I once heard a fellow fortune teller say that some fortune tellers are very accurate, because fate happens to you and will leave traces. Experienced fortune tellers can see 50% to 60% at a glance, and can be accurate to 80% to 90% after dialogue! The future is variable, and your subconscious will resist something you don't agree with in fortune telling, so it is possible to ban it! For example, you will crush a bird in the future. Your subconscious is resisting, and you don't want to crush it. The result is of course not allowed! Of course, The Book of Changes is extensive and profound, and the fortune tellers are mixed, and there are also liars who talk nonsense in it!