There are times in life where you realize just how good you used to have it. There is a magical moment where your bubble is popped, and life really sucks for a while. This moment just barely came for me. I was given surgery on my toe to remove a needle, and now it hurts like it is burning in all the fires of heck if I move it more than a few inches. It’s getting better, but it is a moment where I appreciate much more a life without a very annoying left big toe.

So, how does this relate to writing?
Well, that is a good question. You see, we want these kinds of moments in fiction: moments where the protagonist’s view of everything is shattered. A moment where everything turns reality around, and their past in a much different light. Granted, it should be much more dramatic than realizing that walking around with a needle stuck inside your toe is preferable to the pain following its removal, but it’s the same concept. In the most cliched form of the Hero’s Journey story (the ones that are a clone of starwars and Lord of the Rings), this would be when the Hero realizes he really was doing something to help the villain, or that the villain is actually his father. Now these were dramatic about a decade ago.
These twists used to be fresh and original, but now we’d better do something better. In one of my own stories, Divine Intervention, this moment is when he realizes that no one had ever done anything for him. He realized no one cared about him, that he was just their tool. At this moment, everything was changed for him. He saw his entire journey in a different light, and this caused him to make a decision different than what he originally planned.
We should always work for these kinds of moments in our own writing. It doesn’t need to be a total reversal of the entire story, like the twist in 6th sense, but we need the plot to be dynamic. However, don’t just stick random twists in, make sure they make sense for your story. You also need to foreshadow them (even if it’s not very obvious). Otherwise, you’re story will be like 24. And no story should ever have to endure that.