[HEY, WAIT A MINUTE] "Always in motion the future is..."

The future is always in motion. Any number of things could happen that can change the future outcome. In the case of Anakin, he could have taken Yoda's advice. He chose not to, and as a result, Padme died. In the case of Luke, he also could have taken Yoda's advice. He chose not to, and as a result Yoda's premonition (that Luke could destroy all Leia and Han suffered for) didn't come to pass. It's the present (and the past) that's fixed; once it has arrived, it's immutable. But up until that point, there are any number of possible futures that could come to pass. That's what Yoda meant when he said that the future is always in motion. One could choose to interpret a vision as a likely possible future, but until it happens, it's still only a possible future. Any future is only meant to happen once it already has. And with that, I'm off to take some ibuprofen.

 

The only vision that I can remember not coming true is one by Luke where he saw Mara and Anakin on Dantooine. He says thatthe vision "didnt have a happy endiing" or something of that nature. He and Jacen diresctly set out to prevent it and they did