Who am I?

I am your constant companion.
I am your greatest helper or your heaviest burden.
I will push you onward or drag y0u down to failure.
I am completely at your command.

Half the things you do.
You might just as well turn them over to me.
And i will be able to do them quickly or correctly.
I am easily managed; you must merely be firm with me.

Show me exactly how you want something done.
And after a few lessons, I will do it automatically.
I am the servant of the great people,
And, Alas , of all failure as well.

Those who are great, I have made great.
Those who are failure, I have made failures.
I am not a machine, though I work with the precision.
Of a machine, Plus the Intelligence of a Human.

You May Run Me for profit, or run me for ruin.
It makes no difference to me.
Take me, Train me, be firm with me.
And I will put the world at your feet.
Be easy with me and I will destroy you.
Who am I? I AM HABIT