Who Am I ?? (Genre - Riddle)

Here is a nice riddle I happened to read. It makes for an interesting read and has been very carefully put. Put on your thinking cap to crack this riddle .. and once you have .. read the riddle once more to understand its importance. Bon Chance Mes Amis !!

You may know me.
I'm your constant companion.
I'm you greatest helper.
I'm your heaviest burden.

I will push you onward or drag you down to failure.
I am at your command.
Half the tasks you do can be turned over to me.
I'm able to do them quickly, and
I'm able to do them the same every time.

I'm easily managed.. all you have
to do is to be firm, with me.
Show me exactly how you want it done.
After a few lessons, I will do it automatically.

I' am the servant of all great men and women.
And of course the servant of all the failures as well.
I've made all the great individuals
who have ever been great.
And I've made all the losers too.

I work with all the precision of a computer,
and the intelligence of a human being.
You may run me for profit or you may run me to ruin.
It makes no difference to me.

Make me a strong part of your life.
Be easy with me and I will destroy you.
Be firm with me and I'll put the world at your feet.

Who am I?

Hint : We all have it, some like it, others don't ; Sometimes we like it in ourselves and at other times .. in others ; Others might like it in us and some others might not.... !!
Crack it for a surprise prize .. answer in my next post !!