Brain is a man's CPU (Central Processing Unit) which is responsible for controlling and monitoring activities at that profound level which can't be even thought of! But we are constantly engaging our minds in many P's and F's ( past and future) that we are snatching away the basic operations of brain and hence losing control in activities which requires a static monitoring and regulations.
Many random questions often goes through our mind. What it would result if I do this particular task or activity? How bless I was in childhood! After 10 years where I would be? How lucky I was in my past! How blessfull will be career or future? Will I be able to pass an upcoming examinations? and the "Question banks" occupies a major space in our minds that any solution couldn't survive or rise from fully occupied "thought box." And sometimes we become sick so much of these random queries enquired by us that we become control freak.
Brain itself questions us that how to process the uploaded, "Big Data" into a final result!
It's true that brain gets sharper when its workload multiples but there is one more truth - Excess of something is
harmful. When we think excessively we end up reacting abnormally. Some fatal diseases like depression, migraine, high blood pressure and etc. makes a good connection with us aftermath.
Brain is structured mainly to think of very present. How are we working, how are we acting, how much we are happy and all other 'hows' of present time must be thought by one's brain in order to keep calm the mind and soul.
Let's take one example to understand the concept clearly.
If one robot is programmed specifically to study the plans of one particular project and we are directing it to execute and present us the outcome also, it won't. Or it will stop working and result in fail programming. Similarly, our brain can think of all the three tenses but it will work only for present.
Our brain deceive us to not work for the present but enchant us in the memories of past and dreams of future. Therefore, we easily meet with confusions, frustrations, depressions and lastly recessions at every field.
That's why its suggested to walk in present and talk about present. Along with heart, brain is also needed to be fooled with the universal accepted words, "All is well."