Lucky you. In my case, I end up thinking about the problem in my sleep, come up with solutions that are a mix between reality and fantasy within the dream and usually end in a horrible loop of the above while I desperately try to break out of it. In short, spoils my whole night sleep ( at least how I feel about it next day ). Rarely have it actually produced a successful solution!
My problem too. I actually can't fall asleep because my brain keeps throwing out random ideas at me, like a toddler tugging at my sleeve: "is this solution good enough? no? How about this? No? What about this? No? This?" and so on and so on throughout the night.
Describes perfectly some problems I've had when sleeping. They are not really any problems I think before sleeping and even in my sleep I'm not sure what the problem is but oh boy is my brain thinking hard about it. Usually I need to reset by walking around my apartment for a minute. Thankfully I've had less and less of these nights recently.
Wow, I thought that only happened to me. There was only one specific project I was on where I would have the not so practical fantasy solution like you described. Others were like the parent, a good sleep discovers solutions, I wonder what my subconscious was saying about all of this.
I secretly suspect this is everybody, and the people who claim to be coming up with real solutions in their sleep are back justifying what happened when they had enough time to sleep well and felt nice.
As I also experienced this, the trick is that you keep your mind focused around the problem, even when you go to sleep. I already mentioned you need to make trying to solve the problem your big thing of the day. Of course if you try to solve a problem and at the same day got almost robbed or were close to having an accident (or something really nice happened) your brain is most likely to process that instead at sleep or mix things up.
Claiming that all the engineers, scientists and researchers who claim to use a specific technique to solve problems are really just "back justifyting" seems a bit weird. For the record, I use this technique all the time AND, for the past 8 years, have been getting a solid 8 hours sleep most nights. Why would we do that?