A good place to start is to watch a stream run down a hill. At certain points, the stream encounters a hollow or a depression or a bunch of rocks that block its course. The stream stops there. It cannot go any further. You could say that it is stuck in its practice of running down the hill. What happens? Water continues to flow. The volume of water builds up. But the stream doesn't do anything. It doesn't remove the rocks. It doesn't fill the hollow with earth. A pool forms, perhaps. And, at a certain point, the pool overflows, or the water finds a way through the rocks. Then the streams continues to run down the hill. What is the subjective experience of the stream? Who knows? The stream doesn't think about it.
Practice is like a flowing stream. You make a consistent effort, and the consistent effort gives rise to a continuous flow of energy. Certainly, from time to time you encounter blocks, depressions and confusion. It would hardly be practice if you didn't. As long as the flow of practice continues, your system fills with energy and it finds a way through, over or out. Many people regard those pauses as an indication that something is wrong. Maybe. Maybe not. Subjective assessments of progress are notoriously unreliable. In fact, even being concerned with progress is a bit of a problem. It puts you into a goal-oriented framework in which you think you are responsible for how your practice unfolds. You don't get to decide that, any more than the stream gets to decide how it is going to run down the hill or a flower decides how it is going to bloom.
In today's world, we are losing, or have lost, a simple appreciation of different aspects of life. More and more we hear or read about everyday actions being justified in terms of their economic, evolutionary, medical or other value. Enjoyment for the sake of enjoyment, decency for the sake of decency, etc. seem to be falling by the wayside. Everything has to be justified as making us or the world better in some way.
The same now holds for certain genres of spiritual practice. Many people appear to approach them because it will help them relieve stress or improve the quality of their lives. They approach practice with a definite objective or goal in mind.
Some spiritual methods may certainly have those effects, if that is what you are seeking. But ngöndro and other practices in the Tibetan tradition of Buddhism do not fall into those genres. That is why the notions of progress and achievement have to be questioned. They don't apply. One engages these practices for a different reason. One possibility is that they are response to a calling. Where that calling takes you, no one knows. Thus, you are like the stream, that is called to flow down the hill, but it doesn't know where that will take it or how it will get there or what will become of it in the process.