The point here is Understanding that we are nothing, to make it easier to let go of the material world, or to let go of any pains that befall us. In this way we have calmness, and gain wisdom.
As for your analogy, that our thoughts and selves are an object in motion, which we must curb to reach a desirable point in space: the reality is, there is no object.
Ah, how convenient, a single objective reality where nonexistence is possible :)
To more precisely define my analogy and convey my understanding: current thought is a recurrence relation with previous thoughts. Inertia is the strength of the recurrence relation, the degree by which previous thoughts determine present thought. This is measurable as neural adaptation and learning. Ego or self is an observed distribution of thoughts occurring during a certain duration. As with statistical distributions, we tend to construct parameter estimators to make sense of the data[1].
Now, as with statistics, whether these generated parameters contain information and are useful in describing the distribution is up for debate and dependent on the question the investigator seeks to answer. But simply stating 'there is no object' is as sensical and productive as claiming 'there is no mean, there is no standard deviation'.
[1] http://en.wikipedia.org/wiki/Method_of_moments_(statistics)