That you think life is short is merely because you've forgotten most of it. When you stare at an analog clock, the seconds feel like long eternity.
You think your existence is flawed. Have you concsiously choosen this? You just happened to like the idea that you can be better than you are when you first heard of this. And after multiple tries and fails it feels/looks like something is flawed. But I think it's just a downside of that idea. Your observations clearly show that you cannot control your mind. It's just that sometimes visions of better me are in line with what's happening and sometime's are not.
"But of all the water's secrets, he saw today only a single one-one that struck his soul. He saw that this water flowed and flowed, it was constantly flowing, and yet it was always there; it was always eternally the same and yet new at every moment!"
The interesting thing about the stream is that it is different each day. The stream I live near is a tidal stream, since I live by the ocean. Sometimes the tide is high when I go, so the water is brackish. At those times, I can see puffer fish and some kind of long narrow fish with large eyes and fins that look a bit like wings. When the tide is low, the carp swim from upstream along with the turtles. Blue herons stand in the shallower sections trying to catch the endless minnows that skip through the pebbles in the river bed.
I have often thought to record the stream by taking pictures, or video. But then, to what end? What time shall I go? And in what season? And, if I diligently point out the numerous animals that fill the stream, will I not deprive the viewer of the greatest pleasure -- that of discovering an amazing world where one would think that nothing existed?
I think your stream of consciousness is similar. The value is not in the individual thoughts and ideas, but in the experience of those ideas rushing from one place to another. While it is important to spend time to reflect on and view this wonder, it is not necessary to preserve a snapshot of it. Doing so will only distract you from what is happening now.
A person's life is too short to do all the things he or she imagines even in a single day. Do not waste your lifetime by chasing few ephemeral ideas.