Why do we dream? Seriously the question really bugs me! I'd like to hear your brilliant opinions!!

Our neural architecture is incredibly plastic, and dreams serve an important function in consolidating experience and memory. They are a lot like a disk defrag program on your computer, where they help to sort information and maximize capacity. They are powerful parts of our ability to learn and remember, and our emotional state plays largely into which experiences we remember more profoundly. Dreams help bring together those emotions with our experiences so we remember the important ones better later.

 

In short, dreams allow us to better organize all of the information we absorbed while being awake. They allow us to better remember our experiences, and to alter our behavior as a result of learning through experience.

 

Here's a nice short and interesting page:

http://www.scientificamerican.com/article.cfm?id=why-do-we-dream

because 'directed thinking' (carl jung) is tiring. we have to rest it from time to time.

In the 1980s, I had a programming task at assembler level. The entire program for the machine had to fit in 2K of ROM, so the tightest possible code was required. During certain parts of the programming I had to think in binary and mentally perform cpu tasks (thankfully, it was only an 8-bit processor (8080)).

I experienced several nights where I fell asleep thinking in binary and suddenly woke up at 3 or 4 in the morning needing to write down the code that I had developed while dreaming.

The first time this happened, I had been working on a way to detect leap years from the internal clock when the dream revealed that as the year 2000 was a leap year I did not need to code for century detection. All I needed was to examine the two least significant bits of the year bytes; if they were zero it was a leap year.

This convinced me that sleep and dreams are not to rest the brain but to rest the body and run the brain in "batch mode" with minimum external interference.

now my question is, how can we become conscious that we are in a dream? and consequently, choose what we want to do during that dream..

You should look into the concept of lucid dreaming. There is a lot of information out there.