Our mind is like an ocean always occupied by different thoughts and ideas. Just think about it, have you ever for an instant ever stopped thinking on a problem / issue or topic? Well, I guess not and that pretty much brings out what I mean!
An ocean has innumerable forms of like and objects �embedded� in its waters. If there are beautiful small fishes and corals so exist predators like sharks but the ocean never gives a tumultuous appearance! Isn�t it? It appears calm and from the exterior and only when one takes a plunge in it does he /she get a measure of what lies beneath! Our mind too has several ideas, memories and instances lodged in it. To unravel the depth, we need to have a similar thought process.
We simply cannot empty our minds completely and start thinking from the scratch. It calls for a great deal of control and resolve. One in a million people can empty all the content of the mind and take it to ‘zero’ level. It calls for an enormous amount of mind control and meditation.
However, we can make use of the ideas and thoughts that pop up in our mind. Knowingly or unknowingly, many 
thoughts and ideas come to our mind. But the deal with beautiful ideas is that they are squelched. ‘Squelching’ is what happens when a water bubble bursts with a small sound. Once the water bubble squelches, the beautiful bubble is gone leaving no sign of it. Similarly, some beautiful ideas just disappear leaving no trace of it. Like an ocean one should be wary that it is among the predators and big robust fishes that the small colourful and beautiful fishes exist!
But people who have achieved great things in life had a knack of tapping the full potential of their mind. Einstein, it is said, would ponder as to what it would be like sitting on the top of a light beam. He would ponder as to in such a situation would he be able to see his own face! For a normal person such a thinking process will be absurd or foolish. But if Einstein had not thought in this way, we would not have seen the Theory of Relativity!
Geniuses stumble upon an idea, and work on the same. But we in our daily lives stumble upon such ideas and dismiss the same as useless. The geniuses develop this skill at a fairly young age.
Reasons could be many which lead us to this kind of a outlook, it could be the result of our education system which does not allow the students to think originally! They are encouraged to memorize and reproduce what they memorized without challenging any thing.
Cultivating thoughts is important but more important is harvesting them! It might happen that after sowing the thoughts, you might desert them on impractical ground but the same thought when harvested might revolutionize your life and the lives of those around you. So, look for the small ingenuous idea and nurture it.
So challenge, question and liberate your mind from the slavery of block thinking!