Probably you have already talked about this topic in many threads.
In Asos Jaime, on his way from Harrenhal to KL, makes a dream that influence his decision to come back and rescue Brienne.
You can read it in a psychological way and it makes perfect sense.
You can read it as a rapresentation of jaime's past present and imminent future.
You can read it as a prophecy in long terms. but jaime was sleeping on a weirwood stump.
Does it indicate the dream is necessarily prop