Why are fulfilled prophecies always surprising?

It seems to be a rule, in narrative as well as real life, that when a prophecy comes true and is fulfilled, it will be in some unexpected and surprising fashion. This is the case for the Old Testament prophecies of Christ.

Hence, while some will regard a prophecy as having been-fulfilled, another person may feel that it was fulfilled in some unexpected way - this is, of course, a staple of narrative fiction and myth: that prophecies cannot be eluded, because they are fulfilled in unexpected ways.

< Why? My explanation is that the reason is that prophecies come true not because the future is foreseen, but because the future is influenced such that the prophecy is made to come true.

For example in Psalm 22 of the Authorized (King James) Version of the Bible verses 16-18:

For dogs have compassed me: the assembly of the wicked have inclosed me: they pierced my hands and my feet. I may tell all my bones: they look and stare upon me. They part my garments among them, and cast lots upon my vesture.

These predictions are taken to have been fulfilled by Jesus having been nailed, his bones not broken and his possessions having being divided by the onlooking soldiers. But the manner of fulfilment could not have been predicted from the words of the prophecy which does not mention nails, or a cross, or soldiers.

My impression of this, and other, prophecies is that they are not a result of God having (as it were) seen a picture of what would come - but as God having influenced the on-going situation at the time of the crucifixion such that the prophecies were fulfilled.

But what about free will? Suppose that who put Christ on trial had acquitted him? What then? Well, the prophecies, or some of them, would have been fulfilled in some different way - presumably at a later time - by God's direct action.

Suppose some soldier had tried to break Christ's bones? Well, perhaps the bones would not have broken - having been miraculously strengthened by God's will, or perhaps the blow would have missed its mark (after all, the spear thrust into Christ's side was directed such that it - surprisingly - did not break a bone).

Or, perhaps the bones would have broken and that specific prophecy would not have been fulfilled - but others would have.

My point is that - if God wants a prophecy to be fulfilled, He can make it happen - not by coercing human will, but by great knowledge of men, by the multiplicity of possibly pathways and timescales leading to the same outcome, and great direct power of action on things.