And now to that initial thought. It is obviously connected to another thought but it is one among several others. ( Don't you still see the pattern? ) So, to complete that thought you will have to complete all the thoughts or rather thought trains, connected to it. This looks like a tree. ( Yes! )
I think we do this all the time, right from the time we are born till we die. And the tree we traverse is our life! We all agree that no two of us are the same. This means that our thought-trees are different. Now, we can think of all the thoughts possible and all the possible connections between them. Doing so, we get a huge graph. The way our life goes is the tree that we carve out of this graph.
But we always feel happy to get back to the original thought. This shows we are doing some progress.
Now that we think we know how it works, we can extrapolate this pattern to see what is the ultimate thought which must be the root of our tree.
It must be the one you had when you just started sensing the world. Now what would a baby wonder when it is conscious of the world around it of which it knows nothing. I can think of a few:
1. Where am I?
2. Who am I?
3. Why is there so much blood around! :)
and a few more.
Your whole life you have been wondering this and every thought is connected to this one directly or indirectly. And also the happiness of returning to a thought becomes greater with the size of the tree under it.
So, when you return to the original questions you get the highest possible happiness. This is what I think all our sadhus and such people do. May be this is what they call the "enlightenment" or "bliss". Also since the happiness associated with concluding on a thought gets bigger as the size of the tree underneath it, it is also necessary to traverse as big a tree in thought-graph as possible. But in the end coming back to the root of the tree is just as important. We can see that this is the balance that one always tries to achieve.