So for me, I guess I would call that pretty life changing, but perhaps not in the way that others might think of when they attribute the term "life changing" to lucid dreams. I feel that there is some degree of mastery one acquires over one's own mind with these kinds of exercises. A feeling that this is my mind and I control it. That's always been pretty valuable to me.
"I either needed to make friends with the monster or kill him and that I had the power to do either one."
There is a third possibility: Let it catch you. That's actually how I got rid one of my recurring nightmares. I'd swear there was a second's pause as my brain asked itself "Uh, now what?"
I now fairly frequently get some imagery in my dreams that have the capability to spark nightmares, but they pretty much never get past the very beginning phase, because my brain knows from experience nothing bad can happen. Big scary monster with teeth chasing you? The best answer is to hop right on in. Another big scary monster with teeth inside the first one? Hop right on in again. Recurring dream involving fear of heights? Just fall. Eventually it'll all work itself out.
I now fairly frequently get some imagery in my dreams that have the capability to spark nightmares, but they pretty much never get past the very beginning phase
That's pretty much how I feel as well, except I wouldn't say frequently for me. Occasionally I'll get imagery that is kind of nightmarish, but it usually doesn't seem to escalate beyond a certain point.
Facing one's fears, be they real or imagined usually has some value, in my experience.
It's sort of cute and fun, but I do sometimes wonder if this idea that it's some sort of life changing thing is either A: some people are wired differently enough that it happens for them, but this has little-to-no applicability for the rest of us or B: it's sort of become a New Age-style touchstone of faith that this is some sort of way of overcoming your mind or something and the claims that it's some sort of magical adventure are more wishes than reality, fed by the same sort of feedback loops that run most other New Age sorts of ideas.
Perhaps both.
I do admit to a little fascination by the parameters of what is controllable and what is not, rather more than the dream. This gets perilously close to the "who cares?" sort of dream discussion, but, hey, you're the one reading the comments on HN for an article entitled "Can you teach yourself to control your dreams?", so don't come crying to me about it. I have noticed:
* It is indeed sort of possible to completely rewrite the dream to do something like "win the superbowl", but the effort of the will involved is often enough to just flat wake you up. If you are thinking of getting into lucid dreaming I'd recommend less obtrusive changes. Flying's a good start.
* One common observation is that dreams involve your body image, which is in fact a real sense (related to proprioception but not the same). Your body image is surprisingly fuzzy in some ways; as the article mentions, you might not quite have five fingers. Another one I've found is that I must NOT look in a mirror for any period of time. Seeing your own facial image is distressing enough, then it starts... distorting. It's the same sort of thing as http://growabrain.typepad.com/photos/uncategorized/four_eyes... , only... worse.
* I find that while I fly quite freely, I can't actually get above everything. If I fly above one tree line, the next one is even higher, if I fly above that, there's suddenly an even bigger cliff, eventually I get stuck. I can transition from land into space but only if I close my eyes within the dream during the transition. I think this is actually because I don't fly much, and when I do it is as a passenger on a commercial flight; I have no internal frame of reference for really flying. Amusing while awake, sometimes frustrating when asleep.
* Any given trick only works twice well, then a couple more times with effort, then stops working, in quick succession. If I can walk through walls or windows, it works like that. If I pick up a weapon (hey, I'm a guy), it works like that. Flight tends to work like that. I think it may actually be neural, just like saying the same word continuously for 30 seconds makes the word "stop being a word".
I am aware of the possibility that this is a self-fulfilling prophecy. It may be. Doing any sort of science on this topic would be tricky for this reason, I think. For instance, this article says that light switches never work in dreams... well, mine do about 50% of the time. At least the text or time tests have some science behind them; ISTR claims that those parts of the brain really do shut down more so it makes sense that the vast majority of dreams will have trouble there. Still, every once in a while I do get a bit of stability on some text or something. I try not to think about it too hard, lest my brain talk itself into not giving me any clues it is asleep....